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Main lobe

In antenna theory, the main lobe, also known as the major lobe or main beam, is the radiation lobe within an antenna's pattern that encompasses the direction of maximum radiation intensity, where the antenna concentrates the majority of its radiated or received energy.^[1] The half-power beamwidth (HPBW) provides a common measure of the main lobe's angular width, defined as the angle between the directions where the radiation intensity is half the maximum value of the lobe.^[2] The width and shape of the main lobe are critical parameters that determine the antenna's directivity and gain, with narrower lobes generally providing higher directivity for applications requiring focused energy, such as radar systems and point-to-point communications. The main lobe is distinguished from secondary radiation features like sidelobes and back lobes, which represent undesired energy dispersion in other directions and are minimized in design to reduce interference and improve efficiency.^[2] In practical antenna engineering, the main lobe's performance is quantified through metrics such as the beam solid angle and sidelobe level (SLL), often expressed in decibels relative to the main lobe's peak, with low SLL values (e.g., below -20 dB) being desirable for high-performance systems.^[1] For instance, in phased array antennas, electronic steering adjusts the main lobe's direction without mechanical movement, enabling applications in 5G networks and satellite communications where beam agility is essential.^[3] Overall, optimizing the main lobe enhances the antenna's ability to achieve precise spatial selectivity, making it a foundational concept in electromagnetic engineering.^[4]

Fundamentals

Definition

The main lobe, also known as the main beam or major lobe, is the radiation lobe containing the direction of maximum radiation intensity.^[1] ^[2] This lobe is the most prominent feature in the pattern, encompassing the angular region around the peak where the radiated energy is concentrated.^[5] The radiation pattern provides a graphical representation of how the radiated power varies as a function of angle from the antenna's reference axis, with the main lobe appearing as the central peak of maximum intensity.^[6] In contrast to isotropic radiators, which exhibit uniform radiation in all directions without a dominant lobe, directional antennas feature a main lobe that focuses energy into a specific beam, enhancing efficiency for targeted transmission or reception.

Role in Radiation Patterns

In antenna radiation patterns, the overall structure comprises alternating regions of radiation maxima, known as lobes, and minima, referred to as nulls, which delineate the directional distribution of radiated power.^[1] The main lobe represents the primary maximum, characterized as the strongest and typically the widest such region, often aligned with the antenna's boresight axis—the intended direction of maximum radiation. This lobe is bounded by adjacent nulls, where the radiated intensity approaches zero, distinguishing it from secondary features like side lobes that exhibit lower intensity. Radiation patterns are commonly visualized in polar coordinates, where the radial distance from the origin corresponds to the relative power density, and the angular coordinate represents the observation direction; in this format, the main lobe manifests as the dominant, centrally prominent hump extending farthest from the origin. Alternatively, Cartesian representations plot pattern slices (e.g., elevation or azimuth cuts) as power versus angle, highlighting the main lobe's peak and its separation from nulls and minor lobes for easier analysis of directional properties. These plotting conventions facilitate the assessment of how the main lobe dominates the pattern's structure, encapsulating the bulk of the antenna's radiated energy.^[7] The main lobe plays a pivotal role in signal propagation by defining the primary beam direction and effective angular extent, thereby determining the coverage area over which strong signal transmission or reception occurs in communication systems. In the context of link budgets, the peak intensity within the main lobe establishes the maximum antenna gain, which directly influences the received signal strength and overall system performance by concentrating power toward the target receiver. For instance, in a half-wave dipole antenna, the main lobe forms a broad, doughnut-shaped pattern perpendicular to the antenna axis, providing wide azimuthal coverage suitable for omnidirectional applications, in contrast to the highly focused, narrow main lobe of a parabolic dish antenna, which directs energy along its axis for long-range, point-to-point links.^[8]^[9]

Key Characteristics

Beamwidth

The beamwidth of the main lobe refers to the angular extent over which the majority of the radiated or received energy is concentrated, serving as a key metric for characterizing the directional properties of antennas and apertures. The most widely used measure is the half-power beamwidth (HPBW), defined as the angular separation between the two points on the main lobe where the power density drops to half (or -3 dB) of its maximum value.^[10] This corresponds to a voltage level of $1/\sqrt{2} times the peak, providing a practical indicator of the lobe's effective width in applications such as radar and communications.^[11] Another common definition is the beamwidth at the first nulls (BWFN), also known as the first null beamwidth (FNBW), which measures the full angular width between the first minima (nulls) on either side of the main lobe where the radiation intensity approaches zero.^[12] For antennas with uniform aperture illumination, the BWFN is approximately twice the HPBW, offering a broader assessment of the lobe's span that includes the transition to sidelobes.^[7] The 3 dB beamwidth is synonymous with HPBW in power terms, emphasizing the contour where signal strength halves, which is critical for bandwidth-limited systems.^[13] A narrower beamwidth enhances angular resolution, enabling better discrimination of targets or sources separated by small angles in radar and imaging systems, where the HPBW directly limits the minimum resolvable separation to approximately the beamwidth angle. For instance, in radar, the -3 dB beamwidth determines the azimuthal resolution, proportional to range times beamwidth, allowing finer detail in synthetic aperture imaging.^[14] Beamwidth is inversely proportional to antenna size relative to wavelength, such that larger apertures produce narrower beams for improved directivity. For a uniformly illuminated circular aperture, the HPBW can be approximated as

\text{HPBW} \approx \frac{70\lambda}{D} \quad \text{(degrees)},

where \lambda is the wavelength and D is the aperture diameter.^[15] As an example, for a 1 m diameter dish antenna operating at 3 GHz (\lambda = 0.1 m), the HPBW is approximately 7 degrees, illustrating how modest increases in D significantly tighten the beam for applications like satellite reception.^[15]

Directivity and Gain

The main lobe plays a central role in determining an antenna's directivity, which quantifies the concentration of radiated power in a preferred direction relative to an isotropic radiator. Directivity D is defined as the ratio of the radiation intensity U_{\max} in the direction of the main lobe to the average radiation intensity over all directions, given by the formula

D = \frac{4\pi U_{\max}}{P_{\mathrm{rad}}},

where P_{\mathrm{rad}} is the total radiated power.^[16] This measure highlights how the main lobe focuses energy, with higher directivity corresponding to a narrower and more intense main lobe. Antenna gain G extends this concept by incorporating losses, expressed as G = \eta D, where \eta is the radiation efficiency (ranging from 0 to 1) that accounts for ohmic and other dissipative losses in the antenna structure.^[17] The peak gain occurs in the direction of the main lobe maximum, making the main lobe's shape and intensity critical for achieving high-gain performance in applications requiring directional transmission or reception. For antennas with high directivity, an approximation relates D to the main lobe's half-power beamwidths (HPBWs):

D \approx \frac{4\pi}{\mathrm{HPBW}_{\mathrm{az}} \cdot \mathrm{HPBW}_{\mathrm{el}}},

where \mathrm{HPBW}_{\mathrm{az}} and \mathrm{HPBW}_{\mathrm{el}} are the azimuthal and elevation HPBWs in radians, respectively; their product approximates the beam solid angle in steradians. This holds well for patterns where most power is confined to the main lobe.^[16] A practical illustration is a 1.5 m parabolic reflector antenna operating in satellite communications, which can achieve a gain of 30 dBi, signifying a highly focused main lobe that concentrates power effectively for long-range links.^[18]

Design Considerations

Factors Influencing Shape

The shape of the main lobe in an antenna's radiation pattern is primarily determined by the physical and electrical characteristics of the antenna design, as well as external influences. Antenna geometry plays a crucial role, with the size of the aperture directly affecting the beamwidth; larger apertures result in narrower main lobes due to diffraction limits, where the half-power beamwidth (HPBW) is approximately proportional to λ/D, with D being the aperture dimension and λ the wavelength.^[19]^[20] For example, doubling the aperture size can roughly halve the beamwidth, concentrating energy more tightly in the forward direction. The shape of the aperture also influences the lobe's form: rectangular apertures typically produce a sinc-function-like pattern with asymmetric sidelobes, while circular apertures yield a more symmetric Airy disk pattern characterized by rings of lower intensity.^[21] Feed mechanisms and illumination distribution further modify the main lobe's contours. Uniform illumination across the aperture achieves the narrowest possible beamwidth and highest directivity but at the cost of elevated sidelobe levels. In contrast, tapered illumination—such as parabolic or cosine distributions—reduces sidelobe amplitudes by suppressing edge contributions, though this broadens the main lobe slightly, typically increasing the beamwidth by 10-20% depending on the taper severity.^[22]^[23] These trade-offs are essential in applications requiring balanced pattern control. In array antennas, particularly phased arrays, the configuration of elements governs the main lobe's orientation and form. The main lobe can be electronically steered by applying progressive phase shifts (Δφ) between elements spaced by distance d, with the steering angle θ given by θ = arcsin(Δφ λ / (2π d)). This allows precise control without mechanical movement, though excessive steering can distort the lobe shape due to element pattern interactions. Larger arrays with more elements narrow the lobe similarly to increased aperture size in single elements. Environmental factors, such as radomes and ground reflections, can alter the main lobe's shape post-design. Radomes, while protective, introduce transmission losses and phase distortions that tilt or broaden the lobe, potentially shifting the beam axis by several degrees depending on the radome's dielectric properties and curvature.^[24]^[25] Ground reflections create multipath interference, which can elevate or depress the main lobe in low-elevation angles, effectively tilting it toward the horizon and modifying its effective beamwidth in near-ground scenarios.^[26]^[27] These influences collectively determine the directivity, which measures the main lobe's concentration of radiated power.

Optimization Techniques

Amplitude tapering is a fundamental technique for shaping the main lobe in antenna arrays by applying non-uniform excitation amplitudes across the elements, which reduces sidelobe levels while controlling beamwidth. This method trades off a slight increase in beamwidth for significantly lower sidelobes, enhancing overall directivity and efficiency. Seminal approaches include the Taylor window, which synthesizes line-source distributions to achieve predictable sidelobe envelopes with minimal beam broadening, as originally proposed for narrow beamwidth designs with controlled sidelobe levels. Similarly, the Dolph-Chebyshev distribution optimizes the current amplitudes using Chebyshev polynomials to equalize sidelobe heights at a specified level, providing the narrowest possible main lobe for a given sidelobe suppression, as derived from broadside array theory. These window functions are widely applied in linear and planar arrays to balance main lobe performance against interference from sidelobes. Phase adjustment techniques further refine the main lobe by controlling the relative phases of array elements, enabling precise beam steering without mechanical movement. In conventional arrays, progressive phase shifts across elements tilt the main lobe away from broadside, directing the beam toward desired angles while maintaining symmetry and gain. This is achieved by introducing a linear phase gradient, β = (2πd/λ) sinθ, where d is element spacing, λ is wavelength, and θ is the steering angle. In modern systems, digital beamforming (DBF) extends this capability through software-defined phase and amplitude control at the element or subarray level, allowing real-time adaptation for main lobe enhancement, such as widening or narrowing the beam dynamically to optimize signal-to-noise ratios in varying environments. DBF architectures, often implemented with DSP processors, support multiple simultaneous beams and robust main lobe maintenance against distortions. Metamaterials, particularly frequency-selective surfaces (FSS), offer advanced shaping for the main lobe by manipulating electromagnetic wave propagation to improve symmetry and reduce asymmetries caused by structural imperfections. FSS structures, composed of periodic metallic patterns on dielectric substrates, act as spatial filters that selectively transmit or reflect frequencies, thereby refining the main lobe's contour and enhancing uniformity in radiation patterns. When integrated as superstrates over antennas, these surfaces redirect scattered energy to reinforce the main lobe, improving gain and angular coverage without altering the aperture size significantly. Simulation tools like the finite-difference time-domain (FDTD) and method of moments (MoM) are essential for predicting and iterating main lobe shapes during design, enabling virtual optimization before fabrication. FDTD solves Maxwell's equations in the time domain on a discretized grid, capturing broadband transient responses to model complex interactions and predict lobe contours accurately for irregular geometries. Complementarily, MoM formulates integral equations for surface currents, providing frequency-domain solutions ideal for thin-wire or aperture antennas, with efficient handling of large-scale patterns through matrix reductions. Hybrid FDTD/MoM approaches combine these for comprehensive analysis of embedded antennas, allowing iterative refinement of tapering and phasing to achieve target main lobe characteristics.

Applications

In Antenna Systems

In radar systems, the main lobe facilitates target detection by concentrating transmitted energy and maximizing receiver sensitivity within its defined angular beam, allowing echoes from objects in that direction to be distinguished from noise and clutter. The width of the main lobe directly influences the radar's angular resolution, enabling precise localization of targets, while its high gain ensures sufficient signal strength for detection at range. Scanning techniques, such as mechanical rotation or phased-array steering, direct the main lobe across a broader sector to survey larger areas, though the instantaneous field of view remains constrained by the beam's narrow profile, balancing coverage with resolution.^[28]^[29] In wireless communications, base stations employ the main lobe to focus signals toward specific users via beamforming, which adjusts phase and amplitude across antenna arrays to steer the beam dynamically and boost the signal-to-noise ratio (SNR) by concentrating power and reducing interference from other directions. This directional emphasis enhances link reliability and throughput, particularly in multipath environments. In 5G networks, massive MIMO systems exemplify this by forming narrow, adaptive main lobes that track mobile devices, supporting higher data rates and efficient spectrum use in urban deployments.^[30]^[31] Satellite communication links rely on high-gain antennas with narrow main lobes to achieve the directivity needed for reliable signal propagation over thousands of kilometers, where even minor misalignments can degrade performance. Precise pointing mechanisms, such as gimbaled arrays or attitude control systems, are essential to keep the main lobe aligned with the target satellite or ground station, ensuring optimal energy capture and minimizing atmospheric losses. For instance, X-band and Ka-band systems in small satellites use these antennas to enable high-rate downlinks while demanding sub-degree accuracy to maintain the beam's focus.^[32]^[33] System performance incorporating the main lobe is quantified through the link budget, which accounts for antenna gains derived from the main lobe's directivity. The core relation is given by the Friis transmission equation:

P_r = P_t G_t G_r \left( \frac{\lambda}{4 \pi R} \right)^2

where P_r is the received power, P_t the transmitted power, G_t and G_r the transmitter and receiver antenna gains, \lambda the wavelength, and R the distance; this highlights how main lobe gain amplifies effective power transfer in directional RF links.^[34]

In Acoustics and Optics

In acoustics, the main lobe defines the primary direction of sound sensitivity or radiation in array-based systems, such as microphone and loudspeaker configurations. In microphone arrays, it establishes the focused pickup region for the desired signal, allowing beamforming techniques to enhance directionality and suppress ambient noise through constructive interference in that lobe. For instance, delay-and-sum beamforming aligns phases across elements to narrow the main lobe towards the source, improving signal-to-noise ratios in applications like teleconferencing or hearing aids.^[35] Similarly, in loudspeaker arrays, the main lobe directs acoustic energy towards the target audience, enabling spatial audio rendering and reducing unwanted reflections via adaptive beamforming for noise cancellation in reverberant spaces.^[36] In optics, the main lobe manifests as the central intensity maximum in diffraction patterns from apertures or wavefronts, governing resolution and focus in imaging systems. For telescopes and microscopes, this corresponds to the Airy disk—the diffraction-limited spot size for a point source—where the angular beamwidth is approximately \theta = 1.22 \lambda / D, with \lambda denoting the light wavelength and D the aperture diameter. This relation derives from the first zero of the Airy function in the scalar diffraction integral, setting the Rayleigh criterion for resolvability.^[37] In laser optics, the main lobe of the far-field beam pattern determines propagation efficiency, with array phasing techniques optimizing its narrowness to minimize divergence over long distances.^[38] The formation of main lobes in acoustics and optics draws from analogous wave physics, as both rely on solutions to the scalar Helmholtz equation for propagating disturbances in linear media. Ultrasonic transducers exemplify this cross-domain application, where focused main lobes—achieved via phased array beamforming—enable precise energy delivery in medical imaging, such as echocardiography, mirroring optical confocal techniques for sub-millimeter resolution.^[39]^[40] Distinct environmental influences differentiate the fields: acoustic main lobes distort under speed-of-sound gradients from temperature or salinity changes, broadening the beam in turbulent media like the ocean.^[41] Optical main lobes, conversely, respond to refractive index fluctuations, which induce path bending or scattering in stratified atmospheres or biological tissues.^[42]

Sidelobes and Backlobes

Sidelobes are secondary radiation peaks in an antenna's pattern that appear adjacent to the main lobe, representing weaker but undesired energy distribution in directions offset from the primary beam. These lobes arise primarily from diffraction effects at the antenna's aperture edges or from the array factor in multi-element configurations. Sidelobe levels are typically measured in decibels (dB) relative to the peak of the main lobe, with design goals often targeting suppression to -20 dB or lower to minimize interference in applications like radar and communications.^[14]^[43] Backlobes, in contrast, refer to radiation peaks occurring in the rearward direction, opposite the main lobe, often resulting from imperfections in reflector surfaces, feed spillover, or structural scattering in reflector antennas. These lobes can be particularly problematic in directive systems, as they direct energy away from the intended forward hemisphere. Suppression of backlobes is commonly achieved through the strategic placement of microwave absorbers around the antenna structure or behind the reflector to attenuate rearward propagation.^[44]^[45] The presence of sidelobes and backlobes can lead to significant interference issues, such as increased susceptibility to radio frequency interference (RFI) or elevated system noise temperature from ground pickup, thereby degrading signal-to-noise ratios in sensitive receivers. For instance, in a uniform linear array, the first sidelobe level is approximately -13 dB relative to the main lobe, highlighting the inherent challenge of achieving low secondary radiation without additional design efforts.^[46]^[14] Mitigation strategies for sidelobes often involve amplitude tapering of the excitation currents across the array elements, which reduces the peak sidelobe levels by smoothing the aperture illumination but at the expense of broadening the main lobe and slightly decreasing directivity. Common tapering functions, such as cosine or Taylor distributions, can achieve sidelobe suppression to -25 dB or better, depending on the array size and application requirements. Backlobe control complements these techniques by focusing on structural modifications rather than excitation adjustments.^[47]^[48]

Grating Lobes

Grating lobes are spurious radiation maxima in the far-field pattern of an array antenna that resemble the main lobe in shape and intensity but occur at unintended angles. They arise primarily in phased array antennas with periodic element spacing, where the array factor produces replicas of the main beam due to spatial undersampling of the wavefront. This phenomenon is analogous to temporal aliasing in sampled signals, where the periodicity of the array leads to multiple solutions for the beam direction equation.^[49]^[50] The primary cause of grating lobes is excessive inter-element spacing d relative to the operating wavelength \lambda. In a linear uniform array, the array factor AF(\theta) for N elements is given by:

AF(\theta) = \sum_{n=0}^{N-1} e^{j n (k d \sin\theta + \beta)}

where k = 2\pi / \lambda is the wavenumber, \theta is the angle from broadside, and \beta is the progressive phase shift for beam steering. Grating lobes appear when the argument k d \sin\theta + \beta = 2\pi m for integer m \neq 0, leading to additional peaks at angles \theta_m = \sin^{-1} \left( \frac{m\lambda}{d} - \sin\theta_0 \right), where \theta_0 is the desired beam angle. For d > \lambda/2, these lobes enter the visible region (|\sin\theta| \leq 1), potentially overlapping with the main lobe or causing interference. For instance, with d = 1.5\lambda and broadside steering, grating lobes emerge at approximately \pm 41.3^\circ.^[49]^[51] To suppress grating lobes, element spacing must be constrained to d \leq \lambda/2 for scanning over a full $360^\circ hemisphere without replicas, though practical designs often limit d based on the maximum scan angle \theta_{\max} using d \leq \lambda / (1 + \sin\theta_{\max}). Alternative techniques include non-uniform spacing, such as random or aperiodic arrays, which disrupt the periodicity and reduce grating lobe amplitudes, albeit at the cost of increased sidelobes. Subarraying or amplitude tapering can further mitigate their impact, but these methods trade off directivity or complexity. In applications like radar, grating lobes degrade angular resolution and increase susceptibility to jamming if not controlled.^[50]^[51]

References

[1]
[PDF] IEEE Standard Definitions of Terms for Antennas
Jun 1, 2012 · 2.39 beam (of an antenna). The major lobe of the radiation pattern of an antenna. 2.40 beam angle. See: scan angle. 2.41 beam axis (of a ...
[2]
Beamwidths and Sidelobe Levels - Antenna Theory
The sidelobes are smaller beams that are away from the main beam. These sidelobes are usually radiation in undesired directions which can never be completely ...
[3]
Phased Array Beamforming ICs Simplify Antenna Design
The main lobe transmits radiated energy in the desired location while the antenna is designed to destructively interfere with signals in undesired ...
[4]
Practical Overview of Antenna Parameters - A.H. Systems
As typical with directional antennas, the primary lobe is the only desired lobe, and any other power radiated in other lobes is non-ideal.
[5]
[PDF] Antenna Theory and Design
Various parts of a radiation pattern are referred to as lobes, which may be subclassified into major or main, minor, side, and back lobes. • A radiation lobe is ...
[6]
Antenna Theory - Beam Width - Tutorials Point
In the radiation pattern of an antenna, the main lobe is the main beam of the antenna where maximum and constant energy radiated by the antenna flows.
[7]
[PDF] Antennas & Receivers in Radio Astronomy - NRAO: Socorro
Jun 5, 2012 · Karl Jansky with his antenna. Karl Jansky is now recognized as the Father of. Radio Astronomy. Page 4. Jansky's Antenna. 1932. BW ~40º.
[8]
[PDF] LECTURE 4: Fundamental Antenna Parameters
The radiation pattern (RP) (or antenna pattern) is the representation of a ... main lobe). Page 17. Nikolova 2023. 17. If the antenna has its main beam ...
[9]
[PDF] Antenna Characteristics
For a dipole, this leads to the doughnut pattern in 3D because of the dependence of Eθ on sinθ. Figure 2: 3D radiation pattern of an ideal dipole [1]. Usually, ...
[10]
[PDF] Antennas
The protuberances between the nulls are referred to as lobes, and the main, or major, lobe is in the direction of maximum radiation. There are also side lobes ...
[11]
[PDF] ANTENNAS, SYSTEMS, AND NOISE - Faculty
The half-power beamwidth (HPBW) is the angular width between the half power points (1/ 2 below the maximum on the voltage plot, or –3dB below the maximum on ...
[12]
Antenna Radiation Pattern (Theory) - Amrita Virtual Lab
A common definition is the half power beamwidth(HPBW). The peak radiation intensity is found and then the points on either side of the peak represent half the ...
[13]
[PDF] Fundamental Parameters and Definitions for Antennas
That is, two sources separated by angular distances equal to or greater than FNBW/2 ≈ HPBW of an antenna with a uniform distribution can be resolved. If the ...
[14]
https://www.analog.com/en/resources/analog-dialogue/articles/phased-array-antenna-patterns-part1.html
[15]
Phased Array Antenna Patterns—Part 1 - Analog Devices
Beamwidth. Beamwidth provides a metric of angular resolution for antennas. Most commonly, beamwidth is defined by either the half-power beamwidth (HPBW) or ...
[16]
[PDF] Radio Telescope Theory - NRAO Library
α = Half Power Beam Width. HPBW. Sidelobes. The half power beam width (HPBW) is. HPBW ≈ 1.4 7/d. > (5) where I is the wavelength, d the antenna diametes. The ...
[17]
[PDF] Chapter 31: Antenna Parameters
The directivity of an antenna is defined mathematically as the ratio of the maximum radiation intensity that an antenna creates in a particular direction ...
[18]
https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1290&context=smallsat
[19]
[PDF] Exploiting Link Dynamics in LEO-to-Ground Communications
The ground station consists of a 1.5 m parabolic tracking antenna with 30 dB of gain. ... The example of Figure 6 assumes a zenith satellite pass. Because ...
[20]
Antenna Introduction / Basics - RF Cafe
Antenna with a 20 degree beamwidth has a 20 dB gain. 6. 3 dB beamwidth is approximately equal to the angle from the peak. of the power to the first null (see ...
[21]
[PDF] Effect of antenna size on gain, bandwidth, and efficiency
Antenna size affects gain, bandwidth, and efficiency. Broad-band antennas have max gain similar to uniformly illuminated aperture. Higher gain requires narrow- ...
[22]
Chapter 3 Radio Telescopes and Radiometers
If ohmic losses reduce η, then the gain G in Equations 3.31 through 3.34 should be replaced by the directivity defined by D≡G/η.
[23]
[PDF] Aperture Antennas - ECEn 665
Feb 3, 2015 · A narrow radiation pattern reduces spillover noise but decreases the amount of signal received by the feed from the reflector. We will now ...
[24]
Phased Array Antenna Patterns—Part 3: Sidelobes and Tapering
Tapering provides a method to reduce antenna sidelobes at some expense to the antenna gain and main lobe beamwidth.<|separator|>
[25]
Influence of a Radome on Antenna Performance in - AMS Journals
Feb 1, 2013 · It is obvious that the cross-polar levels are increased significantly by the radome. This increase is mainly seen in between the struts up to ...
[26]
Radiation Pattern Recovery of the Impaired-Radome-Enclosed ...
Jul 31, 2020 · It is well known that radome has adverse effects on the performance of the antenna array while protecting it from outside environments.
[27]
[PDF] The Effects of Ground Reflection and Antenna Characteristics ... - DTIC
In scanning, the main lobe of the antenna pattern moves in a cone whose center, 0, is at the point and train angle of the antenna and whose half angle is the ...
[28]
https://ieeexplore.ieee.org/document/9026061
[29]
A Simply Method for Measuring Radar Antenna Wave Beam Pattern by Horn and Signal Generator
Insufficient relevant content. The provided content snippet from https://ieeexplore.ieee.org/document/9026061 does not contain specific information about the role of the main lobe in radar antenna performance, sensitivity, or resolution. It only includes a title and metadata, with no detailed text or data available in the snippet.
[30]
Radar Antenna - an overview | ScienceDirect Topics
Radar antenna is defined as an equipment that emits and receives electromagnetic waves to explore targets, determine range, locate objects, ...
[31]
Massive MIMO and Beamforming: The Signal Processing Behind the ...
In the cellular communications space, many people think of beamforming as steering a lobe of power in a particular direction toward a user, as shown in Figure ...
[32]
Broad beamforming technology in 5G Massive MIMO - Ericsson
Oct 10, 2023 · Ericsson has developed an efficient method for the creation of broad beams for large antenna arrays that has proven to be very useful in 5G ...
[33]
9.0 Communications - NASA
Moving to higher-gain antennas increases the pointing accuracy required for ... high-gain antenna and pointing mechanism (Surrey Satellite Technology, Ltd.) ...Radio Frequency... · Antennas · On the Horizon RF... · Free Space Optical...
[34]
[PDF] N92-24096 A High Gain Antenna System for Airborne Satellite ...
A high gain antenna for commercial aviation satellite communications is discussed. Electromagnetic and practical design considerations as well as candidate.Missing: links | Show results with:links
[35]
Radio Link Budget: Formula Equation - Electronics Notes
The radio link budget sums the transmitted power along with the gains and loses to determine the signal strength arriving at the receiver input.
[36]
Microphone array beamforming based on maximization of the front ...
Dec 21, 2018 · , 1987) beamforming, where the main lobe is at the angle θ = 0 (endfire direction) and it is assumed that the desired signal propagates also ...
[37]
Beamforming with a circular array of microphones mounted on a ...
Sep 2, 2011 · Beamforming with uniform circular microphone arrays can be used for localizing sound sources over 360 ... main lobe, and maximum side lobe level ( ...
[38]
Effects of wavefront sampling speed on the performance of adaptive ...
scope and has the form of an Airy disk for the case of circular symmetry ... matched to the main lobe of the PSF. The total signal in the main lobe of ...<|control11|><|separator|>
[39]
Beam propagation simulation of phased laser arrays with ...
The beam diameter is inversely proportional to array diameter, as the main lobe of a properly phased DEPA has the same geometric properties as a single aperture ...
[40]
https://ieeexplore.ieee.org/document/9251675
[41]
https://asa.scitation.org/doi/10.1121/1.397147
[42]
Acoustic beam propagation in a turbulent ocean - AIP Publishing
Nov 1, 1988 · Effects of random fluctuations of sound speed in the ocean on acoustic beam propagation are investigated. These effects are especially ...
[43]
Optical detection of small changes in refractive indices in water by ...
A beam was used to produce scattered light from boundaries in water caused by temperature gradients and an attached air bubble. The intensity of the forward- ...
[44]
A study of sidelobe suppression of active array satellite antennas ...
To allow for frequency reuse at the same polarization in satellite antennas the maximum sidelobe level has to be kept typically at 50 dB below the copol ...
[45]
[PDF] Suppression of Radiation in Unwanted Directions Mimowave Shade)
Dec 17, 1996 · This paper addresses several ways to minimize the sidelobe and backlobe radiation from a horn antenna on an aircraft and thereby minimize the ...
[46]
Suppression of Antenna Backscatter on a Nanosat Using a ...
Oct 4, 2019 · A resistively loaded frequency selective surface (FSS) absorber is employed to supress the energy contained in the antenna backlobes, and it is ...
[47]
[PDF] Antennas & Receivers in Radio Astronomy - NRAO
May 23, 2018 · • Antenna sidelobes and backlobes. – Increase system temperature due to ground pick up. – Make antenna susceptible to RFI. – Sidelobes can ...
[48]
Sidelobes - an overview | ScienceDirect Topics
The first and highest sidelobe is only 13.5 dB lower than the main lobe. Sidelobes can cause severe problems in radar, and their reduction or blanking are of ...
[49]
Hierarchical Beamforming Strategies for Source Detection With ...
Jun 14, 2025 · Hann tapering significantly improves sidelobe suppression compared to uniform, at the cost of a moderate increase in the number of elements ...
[50]
Phased Array Antenna Patterns—Part 2: Grating Lobes and Beam ...
... main lobe deviated from mechanical boresight. Therefore,. Equation 6. will ... Balanis, Constantine A. Antenna Theory: Analysis and Design, third edition ...
[51]
Microwaves101 | Grating Lobes - Microwave Encyclopedia
A grating lobe occurs when you steer too far with a phased array and the main beam reappears on the wrong side. Elements must be spaced properly in order to ...
[52]
Grating Lobes in Antenna Arrays
These unintended beams of radiation are known as grating lobes. They occur in uniformly spaced arrays (arrays with an equal distance between adjacent elements)