Showing papers on "Slot antenna published in 2014"

Metamaterial-Based Low-Profile Broadband Mushroom Antenna

Abstract: A metamaterial-based broadband low-profile mushroom antenna is presented. The proposed antenna is formed using an array of mushroom cells and a ground plane, and fed by a microstrip line through a slot cut onto the ground plane. With the feeding slot right underneath the center gap between the mushroom cells, the dual resonance modes are excited simultaneously for the radiation at boresight. A transmission-line model integrated with the dispersion relation of a composite right/left-handed mushroom structure is applied to analyze the modes. The proposed dielectric-filled (er=3.38) mushroom antenna with a low profile of 0.06λ0 ( λ0 is the operating wavelength in free space) and a ground plane of 1.10λ0×1.10λ0 attains 25% measured bandwidth with(|S11| <; - 10dB) 9.9-dBi average gain at 5-GHz band. Across the bandwidth, the antenna efficiency is greater than 76%, and cross-polarization levels are less than -20 dB.

Compact Printed MIMO Antenna for UWB Applications

Abstract: A compact multiple-input-multiple-output (MIMO) antenna is presented for ultrawideband (UWB) applications. The antenna consists of two open L-shaped slot (LS) antenna elements and a narrow slot on the ground plane. The antenna elements are placed perpendicularly to each other to obtain high isolation, and the narrow slot is added to reduce the mutual coupling of antenna elements in the low frequency band (3-4.5 GHz). The proposed MIMO antenna has a compact size of 32 ×32 mm 2 , and the antenna prototype is fabricated and measured. The measured results show that the proposed antenna design achieves an impedance bandwidth of larger than 3.1-10.6 GHz, low mutual coupling of less than 15 dB, and a low envelope correlation coefficient of better than 0.02 across the frequency band, which are suitable for portable UWB applications.

Compact Printed UWB Diversity Slot Antenna With 5.5-GHz Band-Notched Characteristics

Abstract: A novel compact printed ultrawideband (UWB) slot antenna for MIMO/diversity applications is presented in this letter. The antenna consists of two modified coplanar waveguides (CPWs) feeding staircase-shaped radiating elements for orthogonal radiation patterns, where a rectangle stub is placed at 45° between the CPW to ensure high isolations. By etching two split-ring resonator (SRR) slots on the radiators respectively, the band-notched property is achieved. Results show that this antenna meets a 10-dB impedance bandwidth and 15 dB isolation from 2.5 to 12 GHz, with a notched band at 5.5 GHz. The measurements of the radiation patterns and envelope correlation coefficient (ECC) denote that the antenna is suitable for multiple-input-multiple-output (MIMO)/diversity systems. Furthermore, it has a compact size of 48 × 48 mm2, which has been significantly reduced, and it is a good candidate for portable devices.

Compact Half Diamond Dual-Band Textile HMSIW On-Body Antenna

Abstract: A novel wearable dual-band textile antenna, designed for optimal on-body performance in the 2.4 and 5.8 GHz Industrial, Scientific and Medical bands, is proposed. By using brass eye-lets and a combination of conducting and non-conductive textile materials, a half-mode substrate integrated waveguide cavity with ground plane is realized that is very compact and flexible, while still directing radiation away from the wearer. Additional miniaturization is achieved by adding a row of shorting vias and slots. Beside excellent free space performance in the 2.4 and 5.8 GHz bands, respectively, with measured impedance bandwidth of 4.9% and 5.1%, maximal measured free-space gain of 4.1 and 5.8 dBi, and efficiency of 72.8% and 85.6%, very stable on-body performance is obtained, with minimal frequency detuning when deploying the antenna on the human body and when bent around cylinders with radii of 75 and 40 mm. At 2.45 and 5.8 GHz, respectively, the measured on-body gain is 4.4 and 5.7 dBi, with sufficiently small calculated SAR values of 0.55 and 0.90 W/kg. These properties make the proposed antenna excellently suited for wearable on-body systems.

Design of Orthogonal MIMO Handset Antennas Based on Characteristic Mode Manipulation at Frequency Bands Below 1 GHz

Abstract: Multi-antenna design in compact mobile handsets at frequency bands below 1 GHz is very challenging, since severe mutual coupling is commonly induced by simultaneous excitation of the chassis' fundamental dipole mode by more than one antenna element. To address this problem, a novel multi-antenna design approach is proposed herein to obtain efficient and uncorrelated antennas. By manipulating the chassis structure, more than one characteristic mode is enabled to resonate at frequencies below 1 GHz. With proper excitations for different characteristic modes, which are orthogonal to each other, well matched multi-antennas with low coupling and correlation are achieved. A chassis loaded with two T-shaped metal strips above its longer edges is taken as an example modification to illustrate the effectiveness of the proposed design approach at 900 MHz. This modification creates a new characteristic mode which resonates near 900 MHz. Afterward, two antenna feeds were designed to efficiently excite the chassis' fundamental dipole mode and the T-strip mode with very low correlation. The T-strip antenna covers LTE Band 8 (880-960 MHz), and the dipole mode antenna covers both LTE Band 5 (824-894 MHz) and LTE Band 8. The proposed dual-antenna design was found to outperform a reference design significantly, both with and without user interactions (i.e., one-hand and two-hand data grips). Practical aspects of mobile handset antennas are also investigated. The prototype was also fabricated and measured, and the measured results show reasonable agreements with the simulated results.

Compact SRR loaded UWB circular monopole antenna with frequency notch characteristics

Abstract: This paper presents the design of a compact split ring resonator (SRR) loaded coplanar waveguide (CPW) fed ultrawideband circular monopole antenna having frequency notch characteristics. The electromagnetic coupling of the SRR with the CPW yields the frequency notch. Fabricated prototypes were measured and compared with simulations and good agreement was obtained. The impedance and radiation plots confirm the suppression of the desired notch frequency. A theoretical formulation to calculate the notch frequency is also proposed and validated.

Flat Luneburg Lens via Transformation Optics for Directive Antenna Applications

Abstract: The great flexibility offered by transformation optics for controlling electromagnetic radiation by virtually re-shaping the electromagnetic space has inspired a myriad of dream-tailored electromagnetic devices. Here we show a 3D-transformed microwave Luneburg lens antenna which demonstrates high directivity, low side-lobe level, broadband response and steerable capabilities. A conventional Luneburg lens is redesigned accounting for dielectric materials that implement a coordinate transformation, modifying the lens geometry to accommodate its size and shape for easy integration with planar microwave antenna applications. An all dielectric lens is manufactured following a thorough holistic analysis of ceramic materials with different volume fractions of bi-modal distributed titanate fillers. Fabrication and measurements of a 3-D flat Luneburg lens antenna validate the design and confirm a high-directivity performance. A directivity of 17.96 dBi, low side-lobe levels for both main planes ~ -26 dB, excellent directivity performance within the X-band and beam-steering up to 34 ° were achieved.

Low-Profile Dual-Band Textile Antenna With Artificial Magnetic Conductor Plane

Abstract: A dual-band textile antenna loaded with an artificial magnetic conductor (AMC) plane is proposed for WLAN applications. Its dual-band operation is enabled by a rectangular patch in the 2.4 GHz band and a patch-etched slot dipole in the 5 GHz band. Since the AMC approaches a perfect magnetic conductor (PMC) in the 5 GHz band, the slot dipole can be located close to the ground. The proposed antenna is fully fabricated using textiles except for a feeding connector used for testing purposes and a via. Simulations and experiments agree well and validate that this low profile antenna operates with a good reflection coefficient and a high front-to-back ratio (FBR) within the desired bands.

Wide-Band Slot Antenna Arrays With Single-Layer Corporate-Feed Network in Ridge Gap Waveguide Technology

Abstract: Single-layer, wideband, and low-loss corporate-feed networks for slot antenna arrays are described. The antenna is built using ridge gap waveguide technology, formed between two parallel metal plates without the requirements of electrical contact between these plates. The corporate-feed network is realized by a texture of pins and a guiding ridge in the bottom plate, and the radiating slots are placed in the smooth top plate. The paper describes two test antennas: a 4 $\,\times\,$ 1 linear slot array and a 2 $\,\times\,$ 2 planar slot array. Both have been fabricated and tested at Ku- band. The linear array shows more than 20% bandwidth and the 2 $\,\times\,$ 2 array shows a bandwidth of 21% for 10-dB return loss. There are good agreements between measured and simulated patterns for both antennas. Measured gain for the planar array is found to be at least 12.2 dBi over 12–15 GHz band.

Broadband Substrate Integrated Waveguide Cavity-Backed Bow-Tie Slot Antenna

Abstract: A novel design technique for broadband substrate integrated waveguide cavity-backed slot antenna is demonstrated in this letter. Instead of using a conventional narrow rectangular slot, a bow-tie-shaped slot is implemented to get broader bandwidth performance. The modification of the slot shape helps to induce strong loading effect in the cavity and generates two closely spaced hybrid modes that help to get a broadband response. The slot antenna incorporates thin cavity backing (height <;0.03λ 0 ) in a single substrate and thus retains low-profile planar configuration while showing unidirectional radiation characteristics with moderate gain. A fabricated prototype is also presented that shows a bandwidth of 1.03 GHz (9.4%), a gain of 3.7 dBi over the bandwidth, 15 dB front-to-back ratio, and cross-polarization level below -18 dB.

Investigations of SIW Leaky-Wave Antenna for Endfire-Radiation With Narrow Beam and Sidelobe Suppression

Abstract: A new substrate integrated waveguide (SIW) leaky-wave antenna is investigated for endfire-radiation with a narrow beam and sidelobe suppression. Maximum directivity conditions for endfire-radiation from line sources with different amplitude distributions are theoretically discussed as a design aid. Interestingly, for endfire beams it is seen that designs that have a lower sidelobe level can also have a higher directivity, contrary to what is normally encountered for broadside beams. An SIW leaky-wave antenna with tapered transverse slots on only the top and bottom planes is presented. Compared with a previous leaky-wave antenna having uniform transverse slots on the top plane, the presented leaky-wave antenna has a main beam that can radiate exactly at endfire and also has a lower sidelobe level. The design of the low sidelobe antenna is based on the leaky mode, which loses physical significance as the beam is scanned to the endfire direction. Nevertheless, the antenna retains a good beam shape and a low sidelobe level when it radiates at endfire. A prototype is made, and measured results are consistent with theoretical and simulated results.

Wideband Radar Cross Section Reduction of Slot Antennas Arrays

Abstract: A comprehensive analysis aimed at reducing the radar cross section (RCS) of array antennas, preserving at the same time their radiating performance, is presented. A microstrip slot array is considered as a test case to illustrate the proposed strategy for radar cross section reduction (RCSR). It is shown that a remarkable reduction of the radar signature can be accomplished over a frequency band as wide as two octaves by employing an array of periodic resistive elements in front of the radiating apertures. The monostatic and bistatic RCS of the proposed structures are investigated both for normal and oblique incidence. Different arrangements and geometries of the periodic resistive pattern are thoroughly analyzed showing the benefits and the drawbacks in terms of antenna gain and level of the scattered fields. Furthermore, the use of metallic parasitic elements for enhancing the antenna gain is considered, and the scattering phenomena caused by their presence are addressed, taking into account the appearance of grating lobes. The antenna designs are also analyzed by resorting to a bidimensional color plot presenting the variation of the reradiated field both in frequency and spatial domain. The guidelines illustrated by the proposed examples can be easily applied to other antenna architectures.

Development of a Ku-Band Corrugated Conical Horn Using 3-D Print Technology

Abstract: We present the development of a Ku-band (10-16 GHz) corrugated conical horn antenna using 3-D print technology or stereolithography. The antenna is printed using acrylonitrile butadiene styrene (ABS), a thermoplastic, and then coated with conductive aerosol paint. The designed antenna achieves a measured peak gain of 19.6 dBi at 16 GHz with a 1.92:1 VSWR from 11 to 18 GHz. It is shown that 3-D printing is capable of producing sufficient feature sizes that make operation in the microwave/millimeter-wave (MMW) bands possible.

Coordinate input device and mobile terminal

Abstract: A coordinate input device 100 includes a signal generation unit 1 , a transmitting antenna unit 2 , a receiving antenna 3 , and a detection unit 4 . The transmitting antenna unit 2 includes a plurality of antennas that transmits an electromagnetic wave W according to an AC signal. The signal generation unit 1 outputs the AC signal SIG to one of the plurality of antennas of the transmitting antenna unit 2 . The receiving antenna 3 receives the electromagnetic wave W from the transmitting antenna unit 2 . The detection unit 4 obtains an intensity distribution of the electromagnetic wave W corresponding to the positions of a plurality of antennas based on the electromagnetic wave W received by the receiving antenna 3 , and detects a detection position according to the position of a peak in the intensity distribution.

Frequency and Pattern Reconfigurable Slot Antenna

Abstract: A novel frequency and pattern reconfigurable slot antenna is proposed. Slot antenna produces a bidirectional radiation pattern, thus a reflector is positioned behind of the antenna to generate a directional radiation pattern. Two switches are placed in the slot to produce three reconfigurable frequency bands: at 1.82 GHz, 1.93 GHz and 2.10 GHz. The introduction of four slits at the edge of the ground plane offers pattern reconfigurability. To tune the beam angles, three switches are inserted into each slit. By manipulating the phase of upper and lower slits in the ground plane, the proposed antenna is capable of reconfiguring its beam to three different angles at 0°, -15° and +15°. The simulated and measured results of reflection coefficient and radiation patterns are presented and compared.

Bandwidth Enhancement of SIW Horn Antenna Loaded With Air-Via Perforated Dielectric Slab

Abstract: A substrate integrated waveguide (SIW) horn antenna loaded with air-via perforated dielectric slab for bandwidth enhancement is proposed in this letter. The narrow impedance bandwidth of the planar horn antenna is mainly resulting from the discontinuity between the substrate and air. By simply drilling air-vias with different diameters in the substrate extended from the horn aperture, a smooth transition from substrate to air can be achieved, which can enhance the impedance bandwidth of the antenna in much degree. Measured results show that the enhanced impedance bandwidth of 40% from 16 to 24 GHz is obtained with the return loss |S11| below -10 dB. In addition, stable radiation patterns are observed over the entire operating band.

Balance feed differential slot antenna for restraining common-mode noise

Abstract: The invention discloses a balance feed differential slot antenna for restraining common-mode noise Based on a planar substrate integrated waveguide structure, the slot antenna is adopted as a radiating unit; due to different electric field distributions in the substrate integrated waveguide under different stimulation modes, energy can be effectively radiated under the different-mode signal stimulation, and most of energy is reflected under the common-mode signal stimulation Due to the adoption of the antenna of the structure, different-mode signals can be effectively transmitted and received, meanwhile, common-mode signals are restrained from being transmitted and received, and therefore the function of restraining common-mode noise is achieved

Design and Analysis of SIW Cavity Backed Dual-Band Antennas With a Dual-Mode Triangular-Ring Slot

Abstract: Substrate integrated waveguide (SIW) cavity backed dual-band triangular-ring slot (TRS) antennas are proposed for planar integration. First, a low profile dual band 45 ° linearly polarized (LP) antenna is designed and analyzed. The dual-mode TRS is proposed and developed by simultaneously exciting the mode of the slot and the mode of the patch inside the slot. To minimize the antenna size, the lowest mode (TE110 mode) of the SIW cavity is adopted to excite the TRS. The -10 dB impedance bandwidth at the higher band is 5.9%, 58.3% wider than that of the conventional SIW cavity backed slot antenna. The interactions of the SIW cavity, the slot mode and the patch mode are analyzed with circuit models and verified by full wave simulations, which provides a new insight into the SIW cavity backed antennas. Then, by exciting a pair of the 45° LP antennas with an SIW coupler, a circularly polarized (CP) dual band antenna with a small frequency ratio of 1.26 is developed. The two antennas are fabricated and tested, and the measured and simulated results agree well.

Compact Dual-Band Microstrip Antenna for IEEE 802.11a WLAN Application

Abstract: A compact dual-band rectangular microstrip antenna (RMSA) is realized by two different single-slotted single-band rectangular microstrip antennas with slotted ground plane. Each open-ended slot in the single-slotted antenna is responsible to generate a wide impedance band that is shifted to lower frequencies by the effect of the ground slot. The length and position of each open-ended slot is varied to operate the antenna in a suitable resonant band (5.15-5.35 and 5.725-5.825 GHz). The proposed antenna meets the required impedance bandwidth, necessary for dual-band IEEE 802.11a WLAN application (5.125-5.395 and 5.725-5.985 GHz). The dimension of the antenna (12 × 8 × 1.5875 mm3) shows an average compactness of about 53.73% with respect to a conventional unslotted rectangular microstrip patch antenna.

Design and Fabrication of a Dual-Polarization Waveguide Slot Array Antenna With High Isolation and High Antenna Efficiency for the 60 GHz Band

Abstract: We propose a slot array antenna for dual-polarization operation in the 60 GHz band. To realize the dual-polarization, cross-shaped radiating slots and a multilayer feeding structure are employed. A 16 $\,\times\,$ 16-element array is fabricated by diffusion bonding of laminated thin copper plates, which has the advantages of high precision and low loss characteristics. To suppress the grating lobes, we employ several design techniques, such as a thick cavity structure and dense element spacing. The high antenna gain higher than 32.0 dBi and the antenna efficiency near 80.0% are obtained over 60.0–64.0 GHz for two different polarizations. The 1-dB-down gain bandwidths reach 10.4% and 10.9%. High isolation above 50 dB is achieved between the two input ports.

A Novel Transparent UWB Antenna for Photovoltaic Solar Panel Integration and RF Energy Harvesting

Abstract: A novel transparent ultra-wideband antenna for photovoltaic solar-panel integration and RF energy harvesting is proposed in this paper. Since the approval by the Federal Communications Committee (FCC) in 2002, much research has been undertaken on UWB technology, especially for wireless communications. However, in the last decade, UWB has also been proposed as a power harvester. In this paper, a transparent cone-top-tapered slot antenna covering the frequency range from 2.2 to 12.1 GHz is designed and fabricated to provide UWB communications whilst integrated onto solar panels as well as harvest electromagnetic waves from free space and convert them into electrical energy. The antenna when sandwiched between an a-Si solar panel and glass is able to demonstrate a quasi omni-directional pattern that is characteristic of a UWB. The antenna when connected to a 2.55-GHz rectifier is able to produce 18-mV dc in free space and 4.4-mV dc on glass for an input power of 10 dBm at a distance of 5 cm. Although the antenna presented in this paper is a UWB antenna, only an operating range of 2.49 to 2.58 GHz for power scavenging is possible due to the limitation of the narrowband rectifier used for the study.

Triband Circularly Polarized Koch Fractal Boundary Microstrip Antenna

Abstract: A novel single-layer single-probe-feed asymmetrical fractal boundary microstrip antenna is considered for triband circular polarization (CP) operation. Four different structures—without-slot (Ant1), rectangular (Ant2), fractal (Ant3), optimized-fractal-slot (Ant4)—are studied for multiband CP radiation. Perturbation in the structure for triband CP radiation is introduced by employing optimized asymmetrical Koch fractal curves as boundaries of a square patch and embedded rectangular slot. The generated 3-dB axial-ratio bandwidths of Ant 4 are 3.2%, 1.6%, and 3.0% at operating frequencies around 2.45, 3.4, and 5.8 GHz, respectively. Measured results that are in close agreement with the simulation results demonstrate that the proposed antenna is well suited for the WLAN/WiMAX wireless applications.

Topology Optimization of Metallic Antennas

Abstract: We introduce an approach to carry out layout optimization of metallic antenna parts An optimization technique first developed for the optimization of load-bearing elastic structures is adapted for the purpose of metallic antenna design The local conductivity values in a given region are used as design variables and are iteratively updated by a gradient-based optimization algorithm Given a set of time-domain signals from exterior sources, the design objective is here to maximize the energy received by the antenna and transmitted to a coaxial cable The optimization proceeds through a sequence of coarsely-defined lossy designs with successively increasing details and less losses as the iterations proceed The objective function gradient is derived based on the FDTD discretization of Maxwell's equations and is expressed in terms of field solutions of the original antenna problem and an adjoint field problem The same FDTD code, but with different wave sources, is used for both the original antenna problem and the adjoint problem For any number of design variables, the gradient is evaluated on the basis of only two FDTD simulations, one for the original antenna problem and another for the adjoint field problem We demonstrate the capability of the method by optimizing the radiating patch of both UWB monopole and microstrip antennas The UWB monopole is designed to radiate over a wide frequency band 1-10 GHz, while the microstrip patch is designed for single and dual frequency band operation In these examples, there are more than 20,000 design variables, and the algorithm typically converges in less than 150 iterations The optimization results show a promising use of the proposed approach as a general method for conceptual design of near-resonance metallic antennas

Single-Layer Differential CPW-Fed Notch-Band Tapered-Slot UWB Antenna

Abstract: A single-layer differential coplanar waveguide (CPW)-fed notch-band tapered-slot ultrawideband (UWB) antenna is proposed in this letter. In order to achieve the sharp and controllable notch-band characteristic, one pair of half-wavelength stubs and slits are introduced inside the tapered slot and in the circular patches, respectively. Compared to a single-ended CPW-fed UWB antenna, due to adopting the differential feeding structure, the proposed antenna has lower cross polarization. Since all of the structures are printed on the same layer of the substrate, it can be fabricated easily and very suitable to be integrated with RF front-end circuits. The measured -10-dB impedance bandwidth is 126% (from 2.78 to 12.3 GHz), along with a sharp notch band from 5.2 to 6.0 GHz. Good agreement is achieved between the measured results and simulated results.

Design of compact reconfigurable ultra-wideband slot antenna with switchable single/dual band notch functions

Abstract: A compact reconfigurable microstrip slot antenna with switchable single and dual band notch functions for ultra-wideband (UWB) applications is presented in this study. In the proposed structure, an additional resonance is excited by etching two symmetrical notches on the feed-line and thereby a UWB characteristic is obtained. Then, by cutting two slots on the radiating patch and embedding two positive-intrinsic-negative (PIN) diodes along these slots, switchable single and dual band notch performances are added to the antenna performance. By changing the bias states of the PIN diodes, the antenna is capable of exhibiting four different performances of UWB spectrum coverage, UWB coverage with single rejection of the wireless local area network (WLAN) band, UWB coverage with single rejection of the WiMAX and C-band spectrum, and UWB coverage with dual band notch function at the WLAN, the WiMAX and the C-band frequencies. Good agreement between the simulated and the measured results is achieved at different performances of the antenna. The designed antenna has a small size of 20 × 20 mm 2 and the measured results reveal that the fabricated antenna has good radiation behaviour in the UWB frequency spectrum with switchable band notch functions at 3.15-3.85 and 5.43-6.1 GHz which can eliminate the UWB frequency band interference with the WiMAX, the C-band and the WLAN systems.

Wideband LTCC 60-GHz Antenna Array With a Dual-Resonant Slot and Patch Structure

Abstract: This paper presents a wideband 60-GHz antenna array with a dual-resonant slot-patch structure. A multilayered low-temperature co-fired ceramic substrate was used for antenna fabrication. A half-wavelength resonant slot was designed with a backed substrate-integrated waveguide (SIW) cavity to enhance the front radiation. The inverted microstrip center-fed structure was designed for easy signal excitation and superior impedance matching. A parasitic patch was also applied to enhance for bandwidth and gain enhancement. The effects of the SIW cavity-backed slot antenna with and without parasitic patches were empirically examined. The simulated results show that adding parasitic patches increased the resonance of the poles and improved antenna gain by 1.85 dB and bandwidth by 9%. A 2 × 2 dual-resonant slot-patch antenna array was designed to further enhance the gain and bandwidth. The equipment setup for on-chip measurements of gain and radiation patterns was established. The measured S11 showed a wide bandwidth of 23%. The measured gain for the four-element antenna array was 9 dBi with slight fluctuations over the 57-64-GHz frequency range.

Multi-band microstrip-fed slot antenna loaded with split-ring resonator

Abstract: A microstrip-fed compact multi-band slot antenna using a single split-ring resonator (SRR) is proposed. The SRR acting as a loading element introduces multiple lower-order resonances in the antenna, which can be controlled by varying the SRR's dimensions as well as its position with respect to the arm of the slot, without altering the geometry of the radiating slot. The concept is validated by a full-wave simulation study and by measurement on a fabricated prototype. The proposed antenna has satisfactory gain and monopolar radiation patterns in all the operating bands.

CPW-Fed Transparent Antenna for Extended Ultrawideband Applications

Abstract: A novel coplanar waveguide-fed transparent antenna for ultrawideband applications with enhanced bandwidth is presented. In this design, different techniques have been used to broaden the bandwidth. The rectangular radiator of the antenna is equipped by the staircase technique to increase the overlapped resonant frequencies. Moreover, two major and minor symmetrical rectangular stubs are mounted on top of the quarter-circle slot ground by using a dual axis to significantly increase the bandwidth between 3.15 and 32 GHz for VSWR <; 2. AghT-8 transparent thin film is used in the design of the proposed antenna to obtain a very compact size and lightweight structure.

Two-Dimensional Scanning Antenna Array Driven by Integrated Waveguide Phase Shifter

Abstract: A Butler matrix-fed two-dimensional (2-D) scan linearly polarized 2 × 2 microstrip ring antenna array (MRAA) is proposed and validated in low-cost substrate integrated waveguide (SIW) technology for Ka-band applications The highly efficient, compact, and passive beam forming network (BFN) consists of SIW cruciform couplers as coupling unit, and its special topology is well adapted for feeding planar arrays The wideband and high radiation efficiency antenna elements are aperture-coupled through slots etched on the top of a high permittivity SIW feed substrate Such four antenna elements are used to construct 2 × 2 MRAA and to form four fixed beams, one in each quadrant at an elevation angle of 20 ° from the broad side array axis A triangular grid arrangement is chosen to avoid grating lobes in the visible space A 50- Ω grounded coplanar waveguide (GCPW) to SIW transition is used to avoid spurious input feed radiation loss The array is measured to exhibit 3-dB beam width of 30 ° in both of the orthogonal planes, radiation efficiency of 70% for each port, and stable radiation pattern bandwidth of 76% at 265 GHz The physical size of the demonstrated 2 × 2 array is 286λo×286λo×022λo

Broadband Circularly Polarized Microstrip Antenna with Coplanar Parasitic Ring Slot Patch for L-Band Satellite System Application

Abstract: A novel capacitive-coupled probe-fed circularly polarized (CP) microstrip antenna with coplanar parasitic ring slot patch has been proposed for the International Maritime Satellite (INMARSAT) and the Global Positioning System (GPS) applications. The key feature of the design is employing capacitive-coupled four-probe feeds to increase impedance bandwidth and adopting coplanar parasitic ring slot patch to enhance CP bandwidth. The feed network is compact and neat using only T-junction power dividers and phase shifters with shunted short-circuited microstrip stubs for lightning protection. The characteristics of the proposed antenna have been studied by simulation and experiment. The final antenna can produce a ${ S}_{11} 14 dB impedance bandwidth of nearly 27%, a 3-dB axial-ratio bandwidth of nearly 16%, and a gain of higher than 8 dB in the whole maritime satellite communication work band.