Showing papers on "Microstrip antenna published in 2011"
TL;DR: In this paper, a sinusoidally-modulated reactance surface (SMRS) was designed for an arbitrary off-broadside angle, which allows for nearly independent control of the leakage and phase constants along the surface.
Abstract: A simple procedure for designing a sinusoidally-modulated reactance surface (SMRS) that radiates at an arbitrary off-broadside angle is outlined. The procedure allows for nearly independent control of the leakage and phase constants along the surface. Printing an array of metallic strips over a grounded dielectric substrate is discussed as a way to practically implement the theoretical SMRS. A method of mapping the gaps between metallic strips to a desired surface impedance is presented as an efficient alternative to mapping methods used in the past. A printed leaky-wave antenna with a sinusoidally-modulated surface reactance is designed using the procedure mentioned above. The TM-polarized antenna radiates at 30° from broadside at 10 GHz, and exhibits an experimental gain of 18.4 dB. Theoretical, simulated, and experimental results are presented.
364 citations
TL;DR: In this article, a double-layer hollow-waveguide slot array is proposed, where a full-corporate feed waveguide is arranged in the lower layer to suppress the reflection over a wideband.
Abstract: In order to achieve a wide bandwidth characteristic of high gain and high efficiency antennas, a double-layer hollow-waveguide slot array is proposed, where a full-corporate-feed waveguide is arranged in the lower layer. This antenna can be built up easily by the process of diffusion bonding of laminated thin metal etching plates, which has high precision and is possibly a low cost technique. The radiating elements and the feed waveguide are designed to suppress the reflection over a wideband. The predicted bandwidth of the reflection less than -14 dB is 8.3% for a 16 × 16-element array antenna. A test antenna is fabricated in the 60-GHz band, and about 80% antenna efficiency with more than 32 dBi is achieved over 4.8 GHz.
296 citations
TL;DR: In this article, a triple-frequency microstrip-fed planar monopole antenna for multiband operation is proposed and investigated, which has a small overall size of 20 × 30 mm2, and operates over the frequency ranges 2.14-2.52 GHz, 2.82-3.74 GHz, and 5.15-6.02 GHz suitable for WLAN 2.4/5.8 GHz and WiMAX 3.5/5 GHz applications.
Abstract: A novel triple-frequency microstrip-fed planar monopole antenna for multiband operation is proposed and investigated. Defected ground structure (DGS) is used in this antenna, which has a rectangular patch with dual inverted L-shaped strips and is fed by a cross-shaped stripline, for achieving additional resonances and bandwidth enhancements. The designed antenna has a small overall size of 20 × 30 mm2, and operates over the frequency ranges, 2.14-2.52 GHz, 2.82-3.74 GHz, and 5.15-6.02 GHz suitable for WLAN 2.4/5.2/5.8 GHz and WiMAX 3.5/5.5 GHz applications. There is good agreement between the measured and simulated results. Experimental results show that the antenna gives monopole-like radiation patterns and good antenna gains over the operating bands. In addition, effects of both the length of the protrudent strips and the dimensions of the DGS for this design on the electromagnetic performance are examined and discussed in detail.
270 citations
TL;DR: In this paper, a substrate integrated waveguide fed cavity array antenna using multilayered low temperature co-fired ceramic technology is presented and designed at V-band (60 GHz).
Abstract: A substrate integrated waveguide fed cavity array antenna using multilayered low temperature co-fired ceramic technology is presented and designed at V-band (60 GHz). The 8 × 8 antenna array is designed with an enhanced bandwidth of 17.1% and a gain up to 22.1 dBi by reconfiguring radiating elements, feeding network, and the transition. The proposed array antenna also features the merits of compact size, stable performance, and high efficiency.
240 citations
TL;DR: In this article, a compact microstrip line-fed ultrawideband (UWB) tapered-shape slot antenna is presented, which is fabricated onto an inexpensive FR4 substrate with an overall dimension of 22 × 24 mm2.
Abstract: A compact microstrip line-fed ultrawideband (UWB) tapered-shape slot antenna is presented. The proposed antenna comprises a tapered-shape slot and rectangular tuning stub. The antenna is fabricated onto an inexpensive FR4 substrate with an overall dimension of 22 × 24 mm2. The experiment shows that the proposed antenna achieves good impedance matching constant gain, stable radiation patterns over an operating bandwidth of 3-11.2 GHz (115.5%) that covers the entire UWB. The nearly stable radiation pattern with a maximum gain of 5.4 dBi makes the proposed antenna suitable for being used in UWB communication applications.
239 citations
TL;DR: In this paper, the authors proposed a multi-beam leaky-wave pillbox antenna based on three main parts: feeding part (integrated horns), quasi-optical system and radiating part.
Abstract: This work proposes a novel multi-beam leaky-wave pillbox antenna. The antenna system is based on three main parts: feeding part (integrated horns), quasi-optical system and radiating part. The radiating and input parts are placed in two different stacked substrates connected by an optimized quasi-optical system. In contrast to conventional pillbox antennas, the quasi-optical system is made by a pin-made integrated parabola and several coupling slots whose sizes and positions are used to efficiently transfer the energy coming from the input part to the radiating part. The latter consists of a printed leaky-wave antenna, namely an array of slots etched on the uppermost metal layer. Seven pin-made integrated horns are placed in the focal plane of the integrated parabola to radiate seven beams in the far field. Each part of the antenna structure can be optimized independently, thus facilitating and speeding up the complete antenna design. The antenna concept has been validated by measurements (around 24 GHz) showing a scanning capability over ±30° in azimuth and more than 20° in elevation thanks to the frequency scanning behavior of the leaky-wave radiating part. The proposed antenna is well suited to low-cost printed circuit board fabrication process, and its low profile and compactness make it a very promising solution for applications in the millimeter-wave range.
231 citations
TL;DR: An efficient mutual coupling reduction method is introduced in this article for extremely closely placed dual-element microstrip antennas positioned on a finite-sized ground plane for WLAN MIMO application at 5.8 GHz.
Abstract: An efficient mutual coupling reduction method is introduced in this letter for extremely closely placed dual-element microstrip antennas positioned on a finite-sized ground plane for WLAN MIMO application at 5.8 GHz. High isolation can be achieved through a simple slot structure on the ground between the microstrip antennas. The position, length, and width of the slot have been optimized for maximizing the isolation. It is found that more than 40 dB isolation can be achieved between two parallel microstrip antennas sharing a common ground plane. The space distance of these antennas is 17.5 mm ≈ 0.33λ0 from element center to center (side by side of 1.6 mm ≈ 0.031λ0) when the ground plane size is 0.85λ0 × 0.55λ0. Along with this letter, several prototypes were fabricated, and their performances measured to validate the obtained IE3D moment method-based simulation results.
230 citations
Patent•
21 Feb 2011TL;DR: In this paper, a dielectric resonator antenna consisting of a ground plane, operatively coupled with the ground plane and a substrate, having a feeding network consisting of four microstrip lines is presented.
Abstract: The present invention provides a dielectric resonator antenna comprising: a dielectric resonator; a ground plane, operatively coupled with the dielectric resonator, the ground plane having four slots; and a substrate, operatively coupled to the ground plane, having a feeding network consisting of four microstrip lines; wherein the four slots are constructed and geometrically arranged to ensure proper circular polarization and coupling to the dielectric resonator; and wherein the antenna feeding network combines the four microstrip lines with a 90 degree phase difference to generate circular polarization over a wide frequency band.
224 citations
03 Jul 2011
TL;DR: A conformal mm-wave phased array antenna design and packaging integration to provide low loss solution and flexibility for platform integration is presented.
Abstract: 60GHz technology utilizes world wide exempt 5–9GHz bandwidth to provide multi-gigabit high throughput wireless communication in WPAN and WLAN applications. One of the key challenges to enable 60GHz technology is developing mm-wave phased array antenna design and packaging integration with mm-wave ICs. This paper presents a conformal mm-wave phased array antenna design and packaging integration to provide low loss solution and flexibility for platform integration.
209 citations
TL;DR: The design procedure, realization and measurements of an implantable radiator for telemetry applications, inserted in a body phantom, is presented and a good correspondence with theoretical predictions is registered.
Abstract: The design procedure, realization and measurements of an implantable radiator for telemetry applications are presented. First, free space analysis allows the choice of the antenna typology with reduced computation time. Subsequently the antenna, inserted in a body phantom, is designed to take into account all the necessary electronic components, power supply and bio-compatible insulation so as to realize a complete implantable device. The conformal design has suitable dimensions for subcutaneous implantation (10 × 32.1 mm). The effect of different body phantoms is discussed. The radiator works in both the Medical Device Radiocommunication Service (MedRadio, 401-406 MHz) and the Industrial, Scientific and Medical (ISM, 2.4-2.5 GHz) bands. Simulated maximum gains attain -28.8 and - 18.5 dBi in the two desired frequency ranges, respectively, when the radiator is implanted subcutaneously in a homogenous cylindrical body phantom (80 × 110 mm) with muscle equivalent dielectric properties. Three antennas are realized and characterized in order to improve simulation calibration, electromagnetic performance, and to validate the repeatability of the manufacturing process. Measurements are also presented and a good correspondence with theoretical predictions is registered.
208 citations
TL;DR: In this paper, four compact asymmetric-slit microstrip antennas were proposed and studied for circular polarization by cutting asymmetrical slits in diagonal directions onto the square microstrip patches, the single coaxial feed microstrip patch antennas were realized for circularly polarized radiation with compact antenna size.
Abstract: Four compact asymmetric-slit microstrip antennas are proposed and studied for circular polarization. By cutting asymmetrical slits in diagonal directions onto the square microstrip patches, the single coaxial-feed microstrip patch antennas are realized for circularly polarized radiation with compact antenna size. The performances of the proposed antennas with several asymmetric-slit shapes onto the patch radiators are compared. The measured 10-dB return loss and 3-dB axial-ratio bandwidths of the antenna prototype are around 2.5% and 0.5%, respectively. The proposed asymmetric-slit configurations are useful for compact circularly polarized microstrip patch antennas and array design.
TL;DR: This communication presents a new antenna system designed for cognitive radio applications that has been simulated with the driving motor being taken into consideration and a good agreement is found between the simulated and the measured antenna radiation properties.
Abstract: This communication presents a new antenna system designed for cognitive radio applications. The antenna structure consists of a UWB antenna and a frequency reconfigurable antenna system. The UWB antenna scans the channel to discover “white space” frequency bands while tuning the reconfigurable section to communicate within these bands. The frequency agility is achieved via a rotational motion of the antenna patch. The rotation is controlled by a stepper motor mounted on the back of the antenna structure. The motor's rotational motion is controlled by LABVIEW on a computer connected to the motor through its parallel port. The computer's parallel port is connected to a NPN Darlington array that is used to drive the stepper motor. The antenna has been simulated with the driving motor being taken into consideration. A good agreement is found between the simulated and the measured antenna radiation properties.
TL;DR: The co-design approach for the integration of filter and antenna is introduced and the proposed structure provides good design accuracy and filter skirt selectivity as compared to the filter simple cascade with antenna and a bandpass filter of the same order.
Abstract: Synthesis and design of a new printed filtering antenna is presented in this communication. For the requirements of efficient integration and simple fabrication, the co-design approach for the integration of filter and antenna is introduced. The printed inverted-L antenna and the parallel coupled microstrip line sections are used for example to illustrate the synthesis of a bandpass filtering antenna. The equivalent circuit model for the inverted-L antenna, which is mainly a series RLC circuit, is first established. The values of the corresponding circuit components are then extracted by comparing with the full-wave simulation results. The inverted-L antenna here performs not only a radiator but also the last resonator of the bandpass filter. A design procedure is given, which clearly indicates the steps from the filter specifications to the implementation. As an example, a 2.45 GHz third-order Chebyshev bandpass filter with 0.1 dB equal-ripple response is tackled. Without suffering more circuit area, the proposed structure provides good design accuracy and filter skirt selectivity as compared to the filter simple cascade with antenna and a bandpass filter of the same order. The measured results, including the return loss, total radiated power, and radiation gain versus frequency, agree well with the designed ones.
TL;DR: In this article, a metamaterial-inspired low-profile patch antenna is proposed and studied for circularly-polarized (CP) radiation, which is realized by exciting two orthogonally polarized modes simultaneously which are located in the left-handed region.
Abstract: A metamaterial-inspired low-profile patch antenna is proposed and studied for circularly-polarized (CP) radiation. The present antenna, which has a single-fed configuration, is loaded with the composite right/left-handed (CRLH) mushroom-like structures and a reactive impedance surface (RIS) for miniaturization purpose. The CP radiation is realized by exciting two orthogonally-polarized modes simultaneously which are located in the left-handed (LH) region. The detailed antenna radiation characteristics are examined and illustrated with both simulated and experimental results. The CP performance can be controlled in several different ways. This antenna exhibits an overall size of 0.177λ0 × 0.181λ0 × 0.025λ0 at 2.58 GHz and a radiation efficiency around 72%. Finally, based on the proposed CP patch antenna, a compact dual-band dual linearly-polarized patch antenna has also been designed and fabricated. Promising experimental results are observed.
TL;DR: In this paper, two microstrip square open-loop resonators, a coupled line, and a Γ-shaped antenna are used and integrated to be a filter-antenna.
Abstract: Design, fabrication, and measurement of a new compact filter-antenna for modern wireless communication systems are presented in this letter. Two microstrip square open-loop resonators, a coupled line, and a Γ-shaped antenna are used and integrated to be a filter-antenna. The Γ-shaped antenna is excited by a coupled line that is treated as the admittance inverter in filter design. The Γ-shaped antenna performs not only a radiator, but also the last resonator of the bandpass filter. Therefore, near-zero transition loss is achieved between the filter and the antenna. The design procedure follows the circuit approach-synthesis of bandpass filters. Measured results show that the filter-antenna achieves an impedance bandwidth of 16.3% (over 2.26-2.66 GHz) at a reflection coefficient |S11 | <; - 10 dB and has a gain of 2.41 dBi.
TL;DR: A flexible folded slot dipole implantable antenna operating in the Industrial, Scientific, and Medical (ISM) band (2.4-2.4835 GHz) for biomedical applications is presented in this paper.
Abstract: We present a flexible folded slot dipole implantable antenna operating in the Industrial, Scientific, and Medical (ISM) band (2.4-2.4835 GHz) for biomedical applications. To make the designed antenna suitable for implantation, it is embedded in biocompatible Polydimethylsiloxane (PDMS). The antenna was tested by immersing it in a phantom liquid, imitating the electrical properties of the human muscle tissue. A study of the sensitivity of the antenna performance as a function of the dielectric parameters of the environment in which it is immersed was performed. Simulations and measurements in planar and bent state demonstrate that the antenna covers the complete ISM band. In addition, Specific Absorption Rate (SAR) measurements indicate that the antenna meets the required safety regulations.
TL;DR: In this paper, a horizontally meandered strip (HMS) feed technique is proposed to achieve good impedance matching and symmetrical broadside radiation patterns for a single-fed broadband circularly polarized stacked patch antenna, which is suitable for universal ultra-high frequency (UHF) RF identification (RFID) applications.
Abstract: In this paper, a horizontally meandered strip (HMS) feed technique is proposed to achieve good impedance matching and symmetrical broadside radiation patterns for a single-fed broadband circularly polarized stacked patch antenna, which is suitable for universal ultrahigh frequency (UHF) RF identification (RFID) applications. The antenna is composed of two corner truncated patches and an HMS, all of which are printed on the upper side of the FR4 substrates. One end of the HMS is connected to the main patch by a probe, while the other end is connected to an SMA connector. Simulation results are compared with the measurements, and a good agreement is obtained. The measurements show that the antenna has an impedance bandwidth (VSWR <; 1.5) of about 25.8% (758-983 MHz), a 3-dB axial ratio (AR) bandwidth of about 13.5% (838-959 MHz), and a gain level of about 8.6 dBic or larger within the 3-dB AR bandwidth. Therefore, the proposed antenna can be a good candidate for universal UHF RFID readers operating at the UHF band of 840-955 MHz. In addition, a parametric study and a design guideline of the proposed antenna are presented to provide the engineers with information for designing, modifying, and optimizing such an antenna. At last, the proposed antenna is validated in RFID system applications.
TL;DR: In this article, a fractal monopole antenna is proposed for the application in the UWB frequency range, which is designed by the combination of two fractal geometries.
Abstract: A fractal monopole antenna is proposed for the application in the UWB frequency range, which is designed by the combination of two fractal geometries. The first iterations of Giusepe Peano fractal are applied on the edges of a square patch, and a Sierpinski Carpet fractal is formed on its surface. The feed circuit is a microstrip line with a matching section over a semi-elliptical ground plane. The presented antenna has an omnidirectional radiation pattern, a good gain, and high efficiency. The fabrication and measurement data attest to the satisfaction of the design specifications.
TL;DR: In this paper, a novel phased array is presented to extend array scanning range by using pattern reconfigurable antenna elements and weighted thinned synthesis technology, which is capable of reconfiguring its patterns from broadside to quasi-endfire radiation by shifting states of PIN diode switches integrated on parasitic strips.
Abstract: A novel phased array is presented to extend array scanning range by using pattern reconfigurable antenna elements and weighted thinned synthesis technology in this paper. The pattern reconfigurable microstrip Yagi antenna element is used as a basic element in array and it is capable of reconfiguring its patterns from broadside to quasi-endfire radiation by shifting states of the PIN diode switches integrated on parasitic strips. A weighted thinned linear array synthesis technique is analyzed and some interesting conclusions have been made. A linear array composed of eight pattern reconfigurable antenna elements is manufactured to demonstrate the excellent performance of the array. The active element pattern of each element is measured and pre-stored. Based on active element patterns and weighted thinned linear array synthesis technique, the pattern scanning performance of the novel array is synthesized. The results indicate that the array can scan its main beam from φ = -60° to φ = 60° in H-plane with gain fluctuation less than 3 dB while maintaining low side lobes, and the -3 dB beam width coverage is about from φ = -68° to φ = 68°. The performance is superior to the traditional phased array made of wide-beam elements.
TL;DR: In this paper, a 2.45 GHz rectifying antenna (rectenna) using a compact dual circularly polarized (DCP) patch antenna with an RF-dc power conversion part is presented.
Abstract: A 2.45-GHz rectifying antenna (rectenna) using a compact dual circularly polarized (DCP) patch antenna with an RF-dc power conversion part is presented. The DCP antenna is coupled to a microstrip line by an aperture in the ground plane and includes a bandpass filter for harmonic rejections. It exhibits a measured bandwidth of 2100 MHz (10 dB return loss) and a 705-MHz CP bandwidth (3 dB axial ratio). The maximum efficiency and dc voltage are respectively equal to 63% and 2.82 V over a resistive load of 1600 Ω for a power density of 0.525 mW/cm2.
TL;DR: In this paper, a U-shape radiating patch is excited by a T-shape resonator through an inset coupling structure, which acts as a radiator as well as the last stage of the filter.
Abstract: Design, fabrication, and measurement of a compact filtering microstrip antenna with second-order quasi-elliptic broadside antenna gain response are presented. A U-shape radiating patch is excited by a T-shape resonator through an inset coupling structure. The U-shape patch acts as a radiator as well as the last stage of the filter, and the inset coupling structure can be treated as the admittance inverter in filter design. The design procedure follows the circuit approach-synthesis of bandpass filters. The broadside gain of the filtering antenna has two poles in passband and two broadside radiation nulls (zeros) at the band edges for improving selectivity. Compared to the conventional inset-fed microstrip antenna, with a little extra circuit area, the proposed filtering antenna has a flatter passband response, better frequency skirt selectivity, and almost twice wider bandwidth. The measurement result shows a good agreement with the simulations.
TL;DR: In this article, a three-dimensional broadband, low-loss, dual-polarization, and high-directivity lens antenna using gradient index (GRIN) metamaterials, which is composed of multi-layer microstrip square-ring arrays.
Abstract: We present the theoretical modeling and prototype demonstration of a three-dimensional broadband, low-loss, dual-polarization, and high-directivity lens antenna using gradient index (GRIN) metamaterials, which is composed of multi-layer microstrip square-ring arrays. The elements of metamaterials, closed square-ring units of variable sizes, are distributed on the planar substrate to satisfy the radial gradient index function and the axial impedance matching layer configuration of the lens. The gradient-index metamaterials are designed to transform the spherical wave-front into the planar wave-front and to minimize the reflection loss. A prototype lens antenna, which consists of a metal conical horn and the gradient-index lens, are simulated, constructed, and measured. The resemblance of simulation and measurement results shows that the prototype lens antenna maintains low return loss and high directivity on the whole X-band (from 8 GHz to 12 GHz). Compared to the traditional horn antenna, the metamaterial...
TL;DR: The proposed design is an octagonal fractal microstrip patch antenna that can be used for 10 GHz -50 GHz frequency range, i.e., it is a super wideband microstrip antenna with 40 GHz bandwidth.
Abstract: The commercial and military telecommunication systems require ultrawideband antennas. The small physical size and multi-band capability are very important in the design of ultrawideband antennas. Fractals have unique properties such as self-similarity and space-filling. The use of fractal geometry in antenna design provides a good method for achieving the desired miniaturization and multi-band properties. In this communication, a multi-band and broad-band microstrip antenna based on a new fractal geometry is presented. The proposed design is an octagonal fractal microstrip patch antenna. The simulation and optimization are performed using CST Microwave Studio simulator. The results show that the proposed microstrip antenna can be used for 10 GHz -50 GHz frequency range, i.e., it is a super wideband microstrip antenna with 40 GHz bandwidth. Radiation patterns and gains are also studied.
TL;DR: In this paper, a planar microstrip-fed super wideband monopole antenna is proposed to cover DVB-H in L-band (for PMP), DCS, PCS, UMTS, Bluetooth, WiMAX2500, LTE2600, and UWB bands.
Abstract: A planar microstrip-fed super wideband monopole antenna is initially proposed. By embedding a semielliptically fractal-complementary slot into the asymmetrical ground plane, a 10-dB bandwidth of 172% (1.44-18.8 GHz) is achieved with ratio bandwidth >;12:1. Furthermore, the proposed antenna also demonstrated a wide 14-dB bandwidth from 5.4 to 12.5 GHz, which is suitable for UWB outdoor propagation. This proposed antenna is able to cover the DVB-H in L-band (for PMP), DCS, PCS, UMTS, Bluetooth, WiMAX2500, LTE2600, and UWB bands.
TL;DR: In this paper, a broadband circularly polarized patch antenna using an artificial ground (AG) structure with rectangular unit cells as a reflector is presented. And the results show a 10 dB return loss of 48.6% and a 3 dB axial ratio bandwidth of 20.4%.
Abstract: This paper presents a broadband circularly polarized patch antenna using an artificial ground (AG) structure with rectangular unit cells as a reflector. The AG structure changes the reflection phase in accordance with the polarization state of the incident wave. By properly combining the transmitted wave from the antenna and the reflected wave from the AG structure, broadband circular polarization can be obtained. The AG structure and the antenna are simulated using a full-wave solver and the results show a 10 dB return loss bandwidth of 48.6% and a 3 dB axial ratio bandwidth of 20.4%. The measured results are in good agreement with the simulated results. The radiation characteristics of the antenna are almost the same as those for an antenna with a PEC reflector.
TL;DR: In this article, a new design for single-feed dual-band circularly polarized microstrip antennas is presented, where a stacked patch configuration is used for the antenna, and circular polarization is achieved by designing asymmetrical U-slots on the patches.
Abstract: In this letter, a new design for single-feed dual-band circularly polarized microstrip antennas is presented. A stacked- patch configuration is used for the antenna, and circular polarization is achieved by designing asymmetrical U-slots on the patches. The dimensions of the U-slots are optimized to achieve circular polarization in both bands. A prototype has been designed to operate at two frequencies with a ratio of 1.66. Both experimental and theoretical results are presented and discussed. The circularly polarized bandwidth of the antenna is 1.0% at 3.5 GHz (WiMax) and 3.1% at 5.8 GHz (HiperLAN).
Patent•
15 Sep 2011TL;DR: An electrically small dual-band planar tunable UHF/L-band antenna was proposed in this article, which includes a combination of a semi-spiral antenna for UHF frequencies and a microstrip patch antenna for the L-band frequencies.
Abstract: An electrically small dual-band planar tunable UHF/L-Band antenna In one example, the dual-band antenna includes a combination of a semi-spiral antenna for the UHF frequencies and a microstrip patch antenna for the L-band frequencies
TL;DR: Study of possibilities to construct a flexible, lightweight and mechanically robust textile antenna for dual-band satellite use: Iridium and GPS and the developed antenna solution allows integration into clothing.
Abstract: Integrating antennas into fabrics is a potential way for facilitating many applications, such as health monitoring of patients, fire-fighting, rescue work, and space and military personal communications. This paper studies possibilities to construct a flexible, lightweight and mechanically robust textile antenna for dual-band satellite use: Iridium and GPS. Different textile materials were characterized and the most promising materials were used to design, construct, and test a rectangular patch antenna. The gain and axial ratio for both bands is compliant with specifications and relatively stable under most bending conditions. The developed antenna solution allows integration into clothing.
TL;DR: In this paper, a planar array of passive lens elements can be phased to approximate the effect of a curved dielectric lens, and two lenses have been designed to collimate radiation from a feed horn into a beam pointing 20° from broadside.
Abstract: A planar array of passive lens elements can be phased to approximate the effect of a curved dielectric lens. The rotational orientation of each element can provide the required phase shift for circular polarization. The array elements must be designed so that the hand of circular polarization changes as the electromagnetic wave passes through the lens. An element is presented that is based on an aperture-coupled microstrip patch antenna, and two lenses are designed. Each lens has a diameter of 254 mm and contains 349 elements. The elements have identical dimensions but the rotational orientation of each element is selected to provide a specific lens function. The first lens is designed to collimate radiation from a feed horn into a beam pointing 20° from broadside. At 12.9 GHz the aperture efficiency is 48%. The second lens acts as a Wollaston-type prism. It splits an incident wave according to its circular polarization components.
TL;DR: In this article, the authors demonstrate the gain enhancement of an ultrawideband (UWB) antenna, achieved using an appropriately designed multioctave dual-layer frequency selective surface (FSS) reflector.
Abstract: In this letter, we demonstrate the gain enhancement of an ultrawideband (UWB) antenna, achieved using an appropriately designed multioctave dual-layer frequency selective surface (FSS) reflector. The proposed novel FSS reflects effectively in phase over a bandwidth of about 120%. Hence, significant enhancement in antenna gain has been achieved with a low-profile configuration without compromising the impedance bandwidth of the UWB antenna. The proposed FSS reflector has a low transmission coefficient and linearly decreasing phase over an ultra-wide frequency band, which is the key requirement for providing an effectively in-phase reflection at the antenna plane. The composite structure is compact, with a total height of λ/4, where λ is the free-space wavelength at the lowest operating frequency of 3 GHz. Experimental results show an impedance bandwidth of 122%. The antenna gain is maintained around 7.5 dBi from 3 to 7 GHz. Between 7-14 GHz, the antenna is more directive with a gain of about 9 dBi with ±0.5 dB variation. Experimental measurements con firm the predicted wideband antenna performance and gain enhancement due to the FSS reflector.