Showing papers on "Reflective array antenna published in 2015"
TL;DR: Two flexible conformal 4 × 4 ultrawideband antenna arrays (single and dual polarization), in a format similar to that of a bra, were developed for a radar-based breast cancer detection system.
Abstract: Radar-based microwave imaging has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues has been studied over a wide frequency band for this application. We design single- and dual-polarization antennas for wireless ultrawideband breast cancer detection systems using an inhomogeneous multilayer model of the human breast. Antennas made from flexible materials are more easily adapted to wearable applications. Miniaturized flexible monopole and spiral antennas on a 50-μm Kapton polyimide are designed, using a high-frequency structure simulator, to be in contact with biological breast tissues. The proposed antennas are designed to operate in a frequency range of 2–4 GHz (with reflection coefficient (S11) below –10 dB). Measurements show that the flexible antennas have good impedance matching when in different positions with different curvature around the breast. Our miniaturized flexible antennas are 20 mm × 20 mm. Furthermore, two flexible conformal 4 × 4 ultrawideband antenna arrays (single and dual polarization), in a format similar to that of a bra, were developed for a radar-based breast cancer detection system. By using a reflector for the arrays, the penetration of the propagated electromagnetic waves from the antennas into the breast can be improved by factors of 3.3 and 2.6, respectively.
213 citations
TL;DR: In this paper, a frequency diverse array (FDA) antenna with a small frequency increment, as compared with the carrier frequency, across array elements is proposed for range-dependent energy control.
Abstract: i»?Phased-array antennas are known for their capability to electronically steer a beam with high effectiveness, but beam steering is fixed in an angle for all range cells. This paper reviews frequency diverse array (FDA) antennas. Different from a phased array, an FDA uses a small frequency increment, as compared with the carrier frequency, across array elements. The use of a frequency increment generates an array factor that is a function of the angle, the time, and the range, allowing the FDA antenna to transmit the energy over the desired range and angle. In addition to analyzing FDA factor characteristics, this paper investigates FDA potential applications in range-dependent energy control and technical challenges in system implementation, with an aim to call for further investigations on the FDA.
173 citations
TL;DR: There are various enabling technologies available for both design methodologies, making them a suitable choice for the new generation of high-speed, high-gain beam-scanning antennas.
Abstract: A detailed overview of various design methodologies and enabling technologies for beam-scanning reflectarray antennas is presented in this article. Numerous advantages of reflectarrays over reflectors and phased arrays are delineated, and representative beam-scanning reflectarray antenna designs are reviewed. For limited field-of-view beam-scanning systems, utilizing the reflector nature of the reflectarray antenna and the feed-tuning technique can provide a simple solution with good performance. On the other hand, for applications where wideangle scan coverage is required, utilizing the array nature of the reflectarray and the aperture phase-tuning approach are the more suitable choices. There are various enabling technologies available for both design methodologies, making them a suitable choice for the new generation of high-speed, high-gain beam-scanning antennas.
164 citations
TL;DR: A novel dual-band, dual-polarized, miniaturized and low-profile base station antenna operating in the frequency bands of 820-960 and 1710-2170 MHz is designed that meets the stringent design requirements and also meets telecommunications industry standards.
Abstract: In this paper, a novel dual-band, dual-polarized, miniaturized and low-profile base station antenna operating in the frequency bands of 820–960 and 1710–2170 MHz is designed. Elements are arranged such that high-frequency elements are embedded in low frequency elements to reduce volume. A baffle is used to reflect the transmitted power density in the forward direction and also improve isolation between elements. Therefore, surrounding isolation baffles and rectangular baffles are appended around high-frequency elements and low-frequency elements, respectively. The diameter of the proposed antenna cover is only 200 mm, which is smaller than the existing antenna diameter of 280 mm. Compared with the other commonly used antennas, the proposed antenna also has some advantages such as concealment and low profile using a tubular form of radome, which can easily integrate the proposed antenna with the surrounding environment. The measured results verify that the proposed antenna meets the stringent design requirements: voltage standing wave ratio (VSWR) is less than 1.3, the isolation is greater than 30 dB, and the pattern parameters also meet telecommunications industry standards.
154 citations
TL;DR: In this paper, a 10-antenna array operating in the 3.6 GHz band for multi-input multi-output (MIMO) operation in the smartphone is presented, where each antenna in the proposed array is a microstripline-fed open-slot antenna with same small dimensions of 3 × 8 mm2 (0.036λ × 0.096λ).
Abstract: A 10-antenna array operating in the 3.6-GHz band (3400–3800 MHz) for multi-input multi-output (MIMO) operation in the smartphone is presented. Each antenna in the proposed array is a microstripline-fed open-slot antenna with same small dimensions of 3 × 8 mm2 (0.036λ × 0.096λ, λ is the wavelength at 3.6 GHz). The proposed array consists of two symmetric five-antenna arrays disposed, respectively, along two long side edges of the system ground plane of the smartphone. The proposed array is expected to be placed in the narrow spacing between the display panel and the long side edges of the smartphone. Acceptable isolation (better than about 10 dB) and good envelop correlation coefficient (ECC) of less than 0.1 for any two antennas in the proposed array is obtained. The maximum channel capacity of the proposed array in a 10 × 10 MIMO system is calculated to reach about 47 bps/Hz at 20-dB signal-to-noise ratio, which is larger than four times that (11.5 bps/Hz) of the upper limit of an ideal 2 × 2 MIMO system with 100% antenna efficiency and zero ECC between antennas. Details of the proposed 10-antenna array are described, and the experimental results are presented and discussed. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1699–1704, 2015
131 citations
TL;DR: In this paper, the authors present a historical development of phased-array antennas as viewed by the authors, showing that the development of computers and solid-state devices has made arrays a very valuable tool in radio-frequency systems.
Abstract: This paper presents a historical development of phased-array antennas as viewed by the authors. Arrays are another approach to high-gain antennas as contrasted with reflector antennas. They originated a little over 100 years ago and received little attention at first. WWII elevated their importance through use in air defense. Since then, the development of computers and solid-state devices has made arrays a very valuable tool in radio-frequency systems. Radio astronomy and defense applications will continue to push the state of the art for many years.
127 citations
TL;DR: In this paper, a multi-layer periodic array design is proposed for sub-wavelength Fabry-Perot cavity type antennas with enhanced bandwidth performance, achieving 16.9 dBi directivity with 10.7% 3 dB bandwidth.
Abstract: A method for designing sub-wavelength-profile and broadband high-gain planar antennas is presented. A novel multi-layer periodic array design is proposed for sub-wavelength Fabry-Perot cavity type antennas with enhanced bandwidth performance. Three double-sided periodic arrays are designed and optimized, each double-sided array consisting of a capacitive artificial impedance surface (AIS) and an inductive partially reflective surface (PRS) printed on either side of a dielectric substrate. They are placed at about sixth of a wavelength from a ground plane and from each other. Thus, three air cavities are created with a total profile of $\lambda/2$ . The proposed antenna has been simulated using CST Microwave Studio and measured achieving 16.9 dBi directivity with 10.7% 3 dB bandwidth. The gain-bandwidth product of the proposed designs outperforms any previous Fabry-Perot antenna design with this profile.
114 citations
TL;DR: Simulation results show improved DOA estimation accuracy and robustness using microstrip patch antennas as opposed to conventional dipoles and it is shown that the bandwidth of a UCA forDOA estimation is limited only by the broadband characteristics of the directional antenna elements and not by the electrical size of the array.
Abstract: The effect of directional antenna elements in uniform circular arrays (UCAs) for direction of arrival (DOA) estimation is studied in this paper. While the vast majority of previous work assumes isotropic antenna elements or omnidirectional dipoles, this work demonstrates that improved DOA estimation accuracy and increased bandwidth is achievable with appropriately-designed directional antennas. The Cramer–Rao Lower Bound (CRLB) is derived for UCAs with directional antennas and is compared to isotropic antennas for 4- and 8-element arrays using a theoretical radiation pattern. The directivity that minimizes the CRLB is identified and microstrip patch antennas approximating the optimal theoretical gain pattern are designed to compare the resulting DOA estimation accuracy with a UCA using dipole antenna elements. Simulation results show improved DOA estimation accuracy and robustness using microstrip patch antennas as opposed to conventional dipoles. Additionally, it is shown that the bandwidth of a UCA for DOA estimation is limited only by the broadband characteristics of the directional antenna elements and not by the electrical size of the array as is the case with omnidirectional antennas.
107 citations
Patent•
02 Sep 2015TL;DR: In this paper, the bodies of the waveguides are formed by a resin molding method, and surface treatment is performed with respect to inner surfaces of the Waveguides with plating.
Abstract: An array antenna device includes a plurality of slot array antennas which are arranged and each of which includes a plurality of slot antennas and a radiation surface, which is formed to be conformal, and a plurality of waveguides each of which supplies respective power to each of the slot array antennas. After bodies of the waveguides are formed by a resin molding method, surface treatment is performed with respect to inner surfaces of the waveguides with plating.
107 citations
TL;DR: In this article, an ultrawideband, tightly coupled dipole array (TCDA) was proposed to support multiple satellite communication bands, simultaneously such antennas enable weight reduction by replacing multiple antennas and provide spectral efficiency by reusing intermediate frequencies for inter-satellite communication.
Abstract: In space-borne applications, reduction of size, weight, and power can be critical Pursuant to this goal, we present an ultrawideband, tightly coupled dipole array (TCDA) capable of supporting numerous satellite communication bands, simultaneously Such antennas enable weight reduction by replacing multiple antennas In addition, it provides spectral efficiency by reusing intermediate frequencies for inter-satellite communication For ease of fabrication, the array is initially designed for operation across the UHF, L, S, and lower-C bands (06–36 GHz), with emphasis on dual-linear polarization, and wide-angle scanning The array achieves a minimum 6:1 bandwidth for VSWR less than 18, 24, and 31 for 0°, 45°, and 60° scans, respectively The presented design represents the first practical realization of dual polarizations using a TCDA topology This is accomplished through a dual-offset, split unit cell with minimized inter-feed coupling Array simulations are verified with measured results of an ${\bf{8}}\times {\bf{8}}$ prototype, exhibiting very low cross polarization and near-theoretical gain across the band Further, we present a TCDA design operating across the upper-S, C, X, and Ku bands (3–18 GHz) The array achieves this 6:1 bandwidth for VSWR $ at broadside, and VSWR $ at 45° A discussion on design and fabrication for low-cost arrays operating at these frequencies is included
101 citations
TL;DR: In this paper, a 77 GHz transmit-array on dual-layer printed circuit board (PCB) is proposed for automotive radar applications, where coplanar patch unit-cells are etched on opposite sides of the PCB and connected by through-via.
Abstract: A 77-GHz transmit-array on dual-layer printed circuit board (PCB) is proposed for automotive radar applications. Coplanar patch unit-cells are etched on opposite sides of the PCB and connected by through-via. The unit-cells are arranged in concentric rings to form the transmit-array for 1-bit in-phase transmission. When combined with four-substrate-integrated waveguide (SIW) slot antennas as the primary feeds, the transmit-array is able to generate four beams with a specific coverage of $\pm 15^{\circ}$ . The simulated and measured results of the antenna prototype at 76.5 GHz agree well, with gain greater than 18.5 dBi. The coplanar structure significantly simplifies the transmit-array design and eases the fabrication, in particular, at millimeter-wave frequencies.
TL;DR: In this paper, an eight-element linear array is proposed and experimentally studied to illustrate the potential of using high impedance surfaces (HISs) for wide-angle scanning applications.
Abstract: In this paper, an eight-element linear array is proposed and experimentally studied to illustrate the potential of using high impedance surfaces (HISs) for wide-angle scanning applications. An HIS-based horizontal wire antenna with a broad-beam radiation pattern is implemented as the individual radiating elements of the proposed array. The working mechanism of the HIS-based array is investigated as well. The rectangular-mushroom HIS, operating in surface-wave band, contributes to the broad-beam radiation of the individual antenna element as well as the wide scan performance of the array. Measured results show that with uniform magnitude and progressive phase excitation, the array performs a wide scan angle up to 85° in the elevation plane and a realized gain varying from 13.1 to 10.1 dBi. Meanwhile, the side lobe levels (SLLs) are generally less than $-10\;\mathbf{dB}$ over the entire scan region. Good agreement is obtained between the measurements and the simulations.
TL;DR: A successful measurement campaign has demonstrated that a UAV-mounted test source provides a means to accurately validate and calibrate the full-polarized response of an antenna/array in operating conditions, including consequently effects like mutual coupling between the array elements and contribution of the environment to the antenna patterns.
Abstract: One of the most challenging aspects of the new-generation Low-Frequency Aperture Array (LFAA) radio telescopes is instrument calibration. The operational LOw-Frequency ARray (LOFAR) instrument and the future LFAA element of the Square Kilometre Array (SKA) require advanced calibration techniques to reach the expected outstanding performance. In this framework, a small array, called Medicina Array Demonstrator (MAD), has been designed and installed in Italy to provide a test bench for antenna characterization and calibration techniques based on a flying artificial test source. A radio-frequency tone is transmitted through a dipole antenna mounted on a micro Unmanned Aerial Vehicle (UAV) (hexacopter) and received by each element of the array. A modern digital FPGA-based back-end is responsible for both data-acquisition and data-reduction. A simple amplitude and phase equalization algorithm is exploited for array calibration owing to the high stability and accuracy of the developed artificial test source. Both the measured embedded element patterns and calibrated array patterns are found to be in good agreement with the simulated data. The successful measurement campaign has demonstrated that a UAV-mounted test source provides a means to accurately validate and calibrate the full-polarized response of an antenna/array in operating conditions, including consequently effects like mutual coupling between the array elements and contribution of the environment to the antenna patterns. A similar system can therefore find a future application in the SKA-LFAA context.
TL;DR: A novel, compact, single-port antenna combining both UWB and UHF bands is presented, designed to keep compatibility with previous tags generations and provides an overall size reduction, while preserving the radiation performance in both the operating bands.
Abstract: In this work, a novel, compact, single-port antenna combining both UWB and UHF bands is presented. This solution is proposed for next-generation passive RFID tags, performing communication and localization through UWB technology and efficient energy harvesting in the UHF band, but it is also designed to keep compatibility with previous tags generations. The UWB communication is deployed by means of an Archimedean spiral topology, while energy harvesting at UHF is obtained by suitably extending the spiral outer arms, thus realizing a meandered dipole, without affecting the UWB behavior. The single-port architecture provides an overall size reduction, while preserving the radiation performance in both the operating bands. This solution allows a direct connection to future integrated UWB–UHF chips, to standard RFID chips, or to a diplexer for suitably combining the UWB and the UHF functionalities. A prototype of this new antenna, realized on a standard FR-4 substrate, is first presented to validate the proposed novel design. As a second step, the same architecture is scaled on a paper substrate in view of its fully ecocompatible realization to be exploited by future pervasive RFID applications. The compact design of the antenna-feeding network in discrete technology is also presented.
TL;DR: In this article, a high-gain Bull's-Eye leaky-wave horn antenna with sinusoidal profile was designed, fabricated, and experimentally measured at 77 GHz.
Abstract: A high-gain Bull’s-Eye leaky-wave horn antenna working at 77 GHz with sinusoidal profile has been designed, fabricated, and experimentally measured. The influence of the number of periods on the gain and beamwidth is numerically investigated. Experimental measurements show a high gain of 28.9 dB, with low sidelobe level and a very narrow beamwidth in good agreement with results obtained from simulations.
TL;DR: In this paper, the half-mode cavity antennas were theoretically analyzed with a cavity model to allow a direct comparison of size and internal field distribution, and wearable realizations of those two antennas using embroidered conductive shorting/side walls were investigated.
Abstract: The quarter-wave patch and half-mode cavity antennas are two typical designs of half-size resonator antennas that are suitable for wearable applications. Despite their similar appearance, they have distinctively different properties. In this letter, the quarter-wave patch and rectangular half-mode cavity antennas are first theoretically analyzed with a cavity model to allow a direct comparison of size and internal field distribution. On that basis, wearable realizations of those two antennas using embroidered conductive shorting/side walls are investigated. It is demonstrated through full-wave simulations that the designs need to consider the resonance frequency stability against compression at seams, and that design optimization for both antennas will benefit from taking into account all expected bending conditions. With this procedure, the overall operational bandwidth over a range of bending conditions can be markedly improved, and a drift of the resonance frequency with bending can be mitigated. Realizations of the two antennas with conductive textiles and embroidered conductive threads for operation at 2.45 GHz validate the findings.
TL;DR: A genetic algorithm is used to search for a set of small antennas by working only with far-field data and it is shown, as predicted theoretically, that such information in the far zone are sufficient for reconstructing the entire near-field in the exterior region.
Abstract: We provide a study of the relation between the near- and far-fields in antenna systems by working with a concrete design problem. The task of finding an antenna array capable of synthesizing a desired near-field distribution is tackled within the general framework of near-field theories recently proposed in literature. We use a genetic algorithm to search for a set of small antennas by working only with far-field data. It is shown, as predicted theoretically, that such information in the far zone are sufficient for reconstructing the entire near-field in the exterior region. We provide a set of examples demonstrating the procedure and validating the proposals. The methodology can be applied to arbitrary antennas and any desired near-field pattern, and we hope it will help automating design methods in the emerging research area of near-field array synthesis.
TL;DR: It is demonstrated that an antenna optimized in this way shows a high sensitivity when used for near-field detection of a phantom with dielectric properties representative of muscle tissue.
Abstract: We present an approach to design from scratch planar microwave antennas for the purpose of ultra-wideband (UWB) near-field sensing. Up to about 120 000 design variables associated with square grids on planar substrates are subject to design, and a numerical optimization algorithm decides, after around 200 iterations, for each edge in the grid whether it should consist of metal or a dielectric. The antenna layouts produced with this approach show UWB impedance matching properties and near-field coupling coefficients that are flat over a much wider frequency range than a standard UWB antenna. The properties of the optimized antennas are successfully cross-verified with a commercial software and, for one of the designs, also validated experimentally. We demonstrate that an antenna optimized in this way shows a high sensitivity when used for near-field detection of a phantom with dielectric properties representative of muscle tissue.
TL;DR: It is found that the MFB architecture applied in C-band is a more realistic approach when compared to the SFB option, and is the key to get compact feed clusters that can be allocated in large and medium-size platforms.
Abstract: Nowadays, broadband satellites operating at Ka-band and providing high capacity (above 100 Mbps) are mostly based on single-feed-per-beam (SFB) antenna configurations. This antenna farm, using typically three or four reflectors to produce the full dual-band (Tx/Rx) multiple beam coverage, provides high performance but leaves no or little room on the spacecraft for other missions. Accommodation constraints and the desire of operators to maximize and diversify their revenues per satellite have led to several studies on innovative antenna solutions enabling to reduce the number of reflector apertures. Multiple-feed-per-beam (MFB) antenna configurations, using only two apertures, are currently under development for broadband missions at Ka-band. C-band is a more mature business and operators are contemplating the possibility to apply the benefits of multiple beam antennas (MBA) to this frequency band. Due to the lower operating frequency, accommodation constraints are even more stringent and although still scarcely discussed, MFB antenna configurations at C-band are clearly of interest. This paper presents investigations on this topic. In particular, it is found that the MFB architecture applied in C-band is a more realistic approach when compared to the SFB option. Beam Forming Networks (BFNs) with periodic structure is the key to get compact feed clusters that can be allocated in large and medium-size platforms. A new four color scheme compatible with a very compact MFB feed array architecture is introduced.
TL;DR: In this article, a dual-band orthogonally and circularly polarized antenna array with disparate elements is presented, where the coupling between the two bands is suppressed effectively inside the feed network, hence improving isolation.
Abstract: A dual-band orthogonally and circularly polarized antenna array with disparate elements is presented. By using corner-truncated stacked patches as elements, both left hand circular polarization (LHCP) in 12 GHz band and right hand circular polarization (RHCP) in 14 GHz band are realized in a shared antenna aperture. Furthermore, by employing disparate elements, the coupling between the two bands is suppressed effectively inside the feed network, hence improving isolation. The measured results of a four-element array agreed well with the simulated ones, achieving isolation better than 20 dB in the dual bands, and a maximum gain of 13.2 dBic for the LHCP and 13.9 dBic for the RHCP. The proposed array can find applications in satellite communications.
26 May 2015
TL;DR: In this article, a variety of 3D printed microwave antennas are presented including wide band, narrow band, multiband and reconfigurable designs including single layer patch, folded E-patch, a bilateral Vivaldi, Spartan logo and Lego-like assembled antennas.
Abstract: In this paper, a variety of 3D printed microwave antennas are presented including wide band, narrow band, multiband and reconfigurable designs. In particular, single layer patch, folded E-patch, a bilateral Vivaldi, Spartan logo and Lego-like assembled antennas are demonstrated. 3D printing provides significant flexibility in the design of antennas that combine the assembly of both dielectric and metal layers to achieve desired performance characteristics such as resonant frequency and radiation pattern. Also, small Lego-like blocks can be printed that allows in the design and assembly of novel antennas structures using a combination of dielectric and metal coated blocks.
TL;DR: The investigated antennas were designed, fabricated, and subjected to the measurements in both steady and transient states to determine their suitability for operating in a wireless system as a time-modulated linear array.
Abstract: This paper concerns the study of the mm-wave reconfigurable antennas based on S-PIN diodes suitable for using in mm-wave communication systems The investigated antennas were designed, fabricated, and subjected to the measurements in both steady and transient states One selected antenna was incorporated into a wireless system to determine its suitability for operating in such a system as a time-modulated linear array By means of appropriate switching of the antenna, multiple radio frequency (RF) chains were simulated in a receiver having only one RF chain This allowed applying a combining technique for improving the system performance in a presence of a strong interfering signal
Patent•
04 Jun 2015
TL;DR: In this paper, a system for focusing a multiplexed beam includes OAM signal processing circuitry for generating a multiple-input-multiple-output (OAM) multiple-access (MIMO) signal.
Abstract: A system for focusing a multiplexed beam includes OAM signal processing circuitry for generating a multiplexed OAM multiplexed signal. A plurality of antennas comprises an antenna array. An antenna array control circuit controls transmission of the multiplexed OAM signal from each of the plurality of antennas in the antenna array. The antenna array control circuit generates control signals to cause the antenna array to transmit the OAM multiplexed signal from each of the plurality of antennas of the antenna array toward a focus point as a transmission beam and controls a timing of the transmissions of the OAM multiplexed signal from each of the plurality of antennas of the antenna array to cause the transmitted OAM multiplexed signals to arrive at the focus point at substantially a same time.
TL;DR: A novel compact-range wireless access system is proposed for multi-Gb/s data transfer in the 60-GHz band, where large-array antennas in the access point generate a quasi-plane wave and form a stable communication zone proportional to the antenna size.
Abstract: A novel compact-range wireless access system is proposed for multi-Gb/s data transfer in the 60-GHz band. Large-array antennas in the access point generate a quasi-plane wave and form a stable communication zone proportional to the antenna size. The link budget based upon the Friis transmission equation is not applicable as ever in this compact-range communication system. The signal coverage up to 10 m still falls within the Fresnel region of the large-array antenna. Mobile users everywhere within the coverage receive almost constant field strength free of multipath interference. To demonstrate the viability, circularly polarized waveguide slot arrays of various sizes are designed and fabricated. After the evaluation of conventional antenna radio frequency (RF) performance, bit-error rate (BER) and signal-to-noise ratio (SNR) measurements are conducted to evaluate the prototype of a compact-range Gigabit wireless access system.
TL;DR: In this paper, circularly polarized (CP) patch antennas that achieve up to 70% optical transparency by using a wire-mesh patch and by cutting the same grid pattern through the substrate are presented.
Abstract: In this letter, we present circularly polarized (CP) patch antennas that achieve up to 70% optical transparency by using a wire-mesh patch and by cutting the same grid pattern through the substrate. Glass or quartz wafers are therefore not needed, and our antennas may be fabricated on standard ceramic substrates, reducing cost and simplifying construction. Metamaterial loading is incorporated in one patch to control the relative phase difference between the patch’s orthogonal modes, which in turn produces dual-band CP radiation. Our dual-band transparent antenna operates at 2.35 and 2.73 GHz with peak radiation efficiencies of 70% and 78%, respectively.
TL;DR: Practical design aspects of spherical arrays for achieving an optimum configuration to meet a specified goal are discussed and the new concept of sharing the hardware among the radiating elements and the effects of the failure of few of them are studied in detail.
Abstract: Spherical phased array antennas (SPAAs) are of particular interest for transmission of payload data of low earth orbiting (LEO) satellites to the ground stations. They can be designed to scan large part of the radiation sphere with constant directivity. This helps in designing highly agile spacecrafts. In this paper, practical design aspects of spherical arrays for achieving an optimum configuration to meet a specified goal are discussed. The new concept of sharing the hardware among the radiating elements and the effects of the failure of few of them are also studied in detail. Measured results of two arrays with completely different configurations but providing almost similar performance are discussed corroborating the design concept.
TL;DR: In this article, a broadband high-gain bi-layer log-periodic dipole array (LPDA) is introduced for conformal load bearing antenna structures (CLASs) applications.
Abstract: A broadband high-gain bi-layer log-periodic dipole array (LPDA) is introduced for conformal load bearing antenna structures (CLASs) applications. Under the proposed scheme, the two layers of the LPDA are printed on two separate thin dielectric substrates which are substantially separated from each other. A meander line geometry is adapted to achieve size reduction for the array. The fabricated and tested array easily exceeds more than an octave of gain, pattern, and VSWR bandwidth.
TL;DR: In this article, the integration of a low-profile antenna array with a multicrystalline silicon solar cell capable of powering a low power wireless sensor at 2.45 GHz is reported.
Abstract: The integration of a low-profile antenna array with a multicrystalline silicon solar cell capable of powering a low-power wireless sensor at 2.45 GHz is reported. Lattice bus bars on the cell are exploited to minimize antenna shadows from low-profile antennas and transmission lines for a higher output power. The dual inverted-F array improves gain, and beam switching enables the array to sweep a wider coverage angle with larger beamwidths compared to other solar integrated antennas.
TL;DR: In this article, an array of four uniform half-width microstrip leaky-wave antennas (MLWAs) was designed and tested to obtain maximum radiation in the boresight direction.
Abstract: An array of four uniform half-width microstrip leaky-wave antennas (MLWAs) was designed and tested to obtain maximum radiation in the boresight direction. To achieve this, uniform MLWAs are placed at 90 $ ^\circ $ and fed by a single probe at the center. Four beams from four individual branches combine to form the resultant directive beam. The measured matched bandwidth of the array is 300 MHz (3.8–4.1 GHz). Its beam toward boresight occurs over a relatively wide 6.4% (3.8–4.05 GHz) band. The peak measured boresight gain of the array is 10.1 dBi, and its variation within the 250-MHz boresight radiation band is only 1.7 dB.