Rectangular Radiation Patch Research Articles

A Waveguide Shunt Slot-Fed Microstrip Patch Antenna—Analysis Using the Method-of-Moments

This paper presents a new waveguide shunt-slot feed for a microstrip patch antenna that is analyzed using a formulation based on the method-of-moments (MoM). Starting from a generalized formulation, expressions are obtained for a rectangular patch radiator excited by a rectangular slot using entire-domain basis functions with a Galerkin procedure to obtain the moment matrix. Expressions for the dielectric region are derived using Green's function in Fourier transform domain. The developed analysis is used on a prototype C-band radiator presenting details. Subsequently, parametric studies are performed on the key design variables of the configuration, i.e., slot dimensions, axial offset of slot and patch position w.r.t. slot center. A slot length of 0.08λ is found a good initial design estimate to obtain resonance. The variation of coupled power with axial slot offset is reported while showing little effect on resonant frequency. This can be a useful design aid for linear arrays to control amplitude excitations. Patch offset from slot center is found to be noncritical in regard to alignment tolerances. However, changes in coupling factor and resonant frequency are reported. The proposed technique is validated through a commercial e.m. simulator, prototype hardware measurements and comparison to an earlier reported antenna. The paper thus establishes the proposed feeding technique using a developed MoM based analysis and presents useful parametric studies to serve as design aids.

Conformal Band-Notch UWB Monopole Antenna on Finite Cylindrical Substrates

A microstrip-fed new UWB monopole antenna with a band-notch characteristic mounted on the finite cylindrical surface is presented. The proposed antenna consists of a rectangular metal radiation patch fed by a 50 ohm microstrip line and a rectangular ground plane. To achieve ultra-wideband, three modifications are introduced. The first one is to blend the upper and lower corners of the radiating plates. The second one is to remove a circular section from the radiating metal. The third one is to blend the upper corners of the ground plane. The antenna is designed on a substrate with dielectric constant εr=3 and 1.6 mm height. The proposed antenna is conformed on finite cylindrical substrates of radiuses 4, 5 and 6 cm. The cylindrical structures were simulated through CST microwave studio finite element package. The simulation results, obtained via CST package on the return losses, VSWR and radiation pattern of the antenna are presented. For both planar and conformal antennas, results show that the impedance bandwidth of the designed antenna is from 2-18 GHz with a return loss less than -10 dB (VSWR<2) and a band rejection of 5-6 GHz for wireless LAN (WLAN), that includes the band 5.15-5.825 GHz limited by IEEE 802.11.a and HIPERLAN/2 with return loss greater than -10dB. The proposed simple shaped conformal antenna provides a good radiation pattern and gain between 3.84 and 5.96 dBi over the entire frequency band excluding the rejected band.

NUMERICAL INVESTIGATIONS OF NOVEL HIGH-GAIN CIRCULARLY-POLARIZED HYBRID ANTENNA FOR MILLIMETER-WAVE DETECTION AND IMAGING APPLICATIONS

A new improved high gain circularly-polarized antenna for millimeter-wave (MMW) applications is introduced in this paper. The proposed antenna consists of a microstrip rectangular patch radiator with corner-chopped fed by a rectangular aperture in the ground plane. To increase the antenna gain, a hollow rectangular ring dielectric resonator (DR) is installed. The DR and microstrip patch radiator together become as a single antenna element with increased gain. Extensive parametric studies are performed to address the effect of varying the antenna parameters on the operational frequency bandwidth. For further gain enhancement, a hemi-spherical dielectric lens made of high-dielectric constant is installed above the proposed antenna. Simulated results using Computer System Technology Microwave Studio (CST MWS) software programs based on finite integral numerical modeling technique (FIT) have been presented. The proposed novel antenna is considered a good candidate for circularly-polarized and high gain MMW applications for microwave detection and imaging applications.

A Reconfigurable Triple-Notch-Band Antenna Integrated with Defected Microstrip Structure Band-Stop Filter for Ultra-Wideband Cognitive Radio Applications

A printed reconfigurable ultra-wideband (UWB) monopole antenna with triple narrow band-notched characteristics is proposed for cognitive radio applications in this paper. The triple narrow band-notched frequencies are obtained using a defected microstrip structure (DMS) band stop filter (BSF) embedded in the microstrip feed line and an invertedπ-shaped slot etched in the rectangular radiation patch, respectively. Reconfigurable characteristics of the proposed cognitive radio antenna (CRA) are achieved by means of four ideal switches integrated on the DMS-BSF and the invertedπ-shaped slot. The proposed UWB CRA can work at eight modes by controlling switches ON and OFF. Moreover, impedance bandwidth, design procedures, and radiation patterns are presented for analysis and explanation of this antenna. The designed antenna operates over the frequency band between 3.1 GHz and 14 GHz (bandwidth of 127.5%), with three notched bands from 4.2 GHz to 6.2 GHz (38.5%), 6.6 GHz to 7.0 GHz (6%), and 12.2 GHz to 14 GHz (13.7%). The antenna is successfully simulated, fabricated, and measured. The results show that it has wide impedance bandwidth, multimodes characteristics, stable gain, and omnidirectional radiation patterns.

A Novel Printed UWB Slot Antenna With Reconfigurable Band-Notch Characteristics

A novel printed ultrawideband (UWB) slot antenna with reconfigurable band-notch characteristics is presented in this letter. The proposed antenna consists of a modified rectangular radiation patch with a circular and three rectangular-shaped slots etched on it. Additionally, by cutting two triangular-shaped slits on a modified ground plane, practical fractional bandwidth of more than 120% (3.12-12.51 GHz), defined by -10 dB return loss, is achieved. In order to generate single and dual band-notch characteristics, two p-i-n diodes are mounted across the circular slot. The designed antenna has small size of 20 × 20 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with switchable single notched bands of 3.12-3.84 GHz WiMAX and 5-6.07 GHz WLAN, when diode 1 and diode 2 are respectively on. Also, dual bands of 3.12-3.82 and 4.9-6.06 GHz are eliminated from whole frequency band when both diodes are concurrently on.

COMPACT TRIPLE-FREQUENCY PLANAR MONOPOLE ANTENNA FOR WIMAX/WLAN APPLICATIONS

A low-proflle microstrip planar monopole antenna with triple-band operation for WiMAX and WLAN applications is proposed. The antenna has a simple structure which consists of a rectangular radiation patch with an L-shaped slot and an inverted L-shaped stub extending from the ground plane. By etching an L-shaped slot on the rectangular radiation patch, the antenna can excite two resonant modes. The third resonant mode is introduced by extending an inverted L-shaped stub from the ground plane. The designed antenna has a small overall size of 17 ⁄ 30mm 2 . A prototype is designed, fabricated, and then measured. The experimental and simulation results show good impedance bandwidth, radiation pattern and stable gain across the operating bands.

A Novel Tri-Band Circular Slot Patch Antenna with an Ebg Structure for Wlan/WiMAX Applications

In this paper, an electromagnetic band-gap (EBG) structure is proposed to achieve tri-band operation for a novel circular slot patch antenna, which is suitable for WLAN and WiMAX applications. The proposed antenna consists of a rectangular radiation patch with an etched circular slot, a circular ring, and a mushroom-like EBG structure, all of which are printed on the top side of the substrate. By embedding a circular ring in the circular slot, the antenna can generate two impedance bandwidths. With the use of EBG structure, the proposed antenna can operate in three separate bands. Simulation results are compared with the measurements, and a good agreement is obtained. The measured results show that the 10 dB return loss bandwidths of the proposed antenna are 530 MHz (2.28–2.81 GHz), 470 MHz (3.29–3.76 GHz) and 1250 MHz (4.87–6.12 GHz), which can cover all the 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands. In addition, a design evolution and a parametric study of the proposed antenna are presented to provide information for designing, modifying, and optimizing such an antenna. At last, good omnidirectional radiation patterns with appreciable gain are obtained over the operating bands.

A NOVEL TRAPEZOIDAL SLOT PATCH ANTENNA WITH A BEVELED GROUND PLANE FOR WLAN/WIMAX APPLICATIONS

A novel trapezoidal slot patch antenna with an embedded trapezoidal strip is proposed for satisfying wireless local area network (WLAN) and worldwide interpretability for microwave access (WiMAX) applications simultaneously. The proposed antenna consists of a rectangular radiation patch with an etched trapezoidal slot and an embedded trapezoidal strip on the top and a beveled ground on the bottom side. By carefully selecting the width of the radiation patch and length of the beveled ground, the proposed antenna can generate two separate bands. The measured results show that the 10dB return loss bandwidths of the proposed antenna are 430MHz (2.30{2.73GHz) and 3460MHz (3.21{6.67GHz), which can cover both the WLAN bands (2.4{2.484GHz, 5.15{5.35GHz, and 5.725{ 5.825GHz) and the WiMAX bands (2.4{2.6GHz, 3.4{3.6GHz, and 5.25{5.85GHz). Furthermore, good omnidirectional radiation patterns with appreciable gain are obtained over the operating bands.

A NOVEL TRI-BAND PRINTED MONOPOLE ANTENNA WITH AN ETCHED ∩-SHAPED SLOT AND A PARASITIC RING RESONATOR FOR WLAN AND WIMAX APPLICATIONS

A novel tri-band printed monopole antenna with an etched \-shaped slot and a parasitic ring resonator is proposed for satisfying wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications simultaneously. The proposed antenna comprises a rectangular radiation patch with an arc- shaped edge and an embedded \-shaped slot on the top and a parasitic ring resonator on the opposite side. The measured results show that the impedance bandwidths of the proposed antenna, deflned by voltage standing wave ratio (VSWR) • 1:5, are 350MHz (2370{2720MHz), 680MHz (3390{4070MHz) and 1080MHz (4920{6000MHz), which cover the required bandwidths for both WLAN (2400{2480MHz, 5150{5350MHz, 5725{5825MHz) and WiMAX (2500{2690MHz, 3400{3690MHz, 5250{5850MHz) applications. Furthermore, good monopole-like radiation characteristics with moderate peak gains are obtained over the operating bands.

The band‐notch function for a printed ultra‐wideband monopole antenna with E‐shaped slot

AbstractIn this study, a printed rectangular monopole antenna with a band‐notch function is proposed for ultra‐wideband (UWB) applications. The notched frequency band is achieved by embedding an E‐slot in the rectangular radiation patch. The notched frequency band can be controlled by adjusting the location, length, and the width of the slot. A design example for an UWB monopole antenna with a notched frequency band at 5 GHz is demonstrated. The antenna also shows omnidirectional radiation patterns across the whole operating bandwidth that is suitable for UWB applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2048–2052, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23582

Band-Notched Characteristics for CPW-fed Printed Monopole Antenna with E Shape Slot

A printed rectangular monopole antenna fed by a tapered coplanar waveguide (CPW) with a band-notched characteristic is proposed for ultra wideband (UWB) applications. It is shown that the notched or rejected band with a wide operating bandwidth is obtained by embedding an E shape slot in the rectangular radiation patch and its parameters studied in detail. The notched band is controllable by adjusting the lengths, location and the width of the slot. With a compact size of 36 × 34 mm2, the proposed antenna showing omni-directional radiation patterns with a notched frequency band at 5 GHz is demonstrated, which is suitable for UWB applications.

Printed Antennas Tuned by Transversely Magnetized Ferrite Operating at a Novel Resonant Mode

The excitation of a novel single mode in the negative efi area is studied for rectangular patch antenna printed on magnetized ferrite substrates or tuned by a ferrite inclusion. In all cases the DC magnetic fleld is considered perpendicular to the substrate plane. The ferrite inclusion-post shape is considered either cylindrical or rectangular. Numerical simulation results reveal the existence of this novel resonating mode inside the negative efi area for both the rectangular microstrip patch printed on ferrite substrate or tuned by a rectangular ferrite post. Also, the input impedance characteristics of these patch antennas are studied. 1. INTRODUCTION A number of published works (e.g., Pozar (1)) show that in the case of patch antennas printed on transversely magnetized ferrite substrates, there is a cutofi frequency range where there is not any propagating mode in the substrate below the radiator. In this range the efiective permeabil- ity efi of the ferrite is negative, so the corresponding wavenumber becomes imaginary leading to an evanescent mode. The resonant frequency of circular and ring patch antennas printed on transversely magnetized ferrite substrate was analytically studied in our previous works (2,3). The analysis was performed using the perfect magnetic walls approximation and the ferrite losses were also taken into account. Closed form expressions were given for all the geometries studied. By including ferrite losses in our analysis and with the proper mathematical handling of the involved Bessel functions, the solution of the characteristic equation in the negative efi area became possible revealing a novel single propagating mode. There is only one similar work published in the litera- ture reporting on this mode as propagating in a grounded ferrite substrate (4). Baccarelli etal. (4) have also considered a lossy ferrite substrate, but biased with an HDC parallel to the ground plane. Assuming propagation along the substrate, but in a direction transverse to the HDC, they indeed found a single mode denoted as TE1+ in the region of negative efi . Our previous studies on axially symmetric patches proved that the novel mode exists in the negative efi range independent of the speciflc patch shape or the tuning ferrite inclusion. This observation motivated us to study the rectangular patch printed on transversely magnetized ferrite substrate and the same patch tuned by a circular or rectangular ferrite post. Thus, the aim of the present work is to identify the existence of any resonant mode in the negative efi range, for rectangular patch radiators.

Modeling a Low-profile Reflect Array Antenna

The theoretical analysis of a planar reflect-array antenna consisting of a rectangular microstrip patch radiators is presented. Such an antenna is to be designed to convert spherical wave radiated by feed horn antenna into plane wave by phasing of reflected wave due to adjusting the patch sizes and arranging them by principle of Fresnel mirror. The modelling of array antenna is based on the modelling of elementary equivalent waveguide cell consisting patch radiator at the interface between superstrate and grounded substrate layers. Spectral Domain Approach (SDA) of Method of Moments is used to analyse the characteristics of elementary waveguide cell. Theoretical and experimental results are compared.

Phase modulated active antenna

The Letter demonstrates that an active microstrip antenna consisting of a rectangular patch radiator peripherally loaded with a GaAs MESFET can be operated simultaneously as a signal source and as a phase modulator. The experimental and simulated results presented illustrate the degree to which phase modulation can be obtained by applying variable DC bias to the active antenna in the presence of a fundamental frequency injection locking signal.

Dual-band reactively loaded microstrip antenna

A previously derived theory is applied to a microstrip antenna with a reactive load to produce a dual-band radiator. A model consisting of a rectangular patch radiator loaded with a variable length short-circuited coaxial stub was investigated experimentally. Comparisons of theoretical predictions and experimental data are made for the impedance and resonant frequencies as a function of the position of the load, the length of the stub, and the characteristic impedance of the stub.

Microstrip patch array antenna

A microstrip array with mutual coupled rectangular patch radiators is described. By the avoidance of a corporate feeding network, advantages in the antenna performance and design are realisable. Experimental results are presented for both linearly and circularly polarised antennas which demonstrate the usefulness of this special antenna configuration.

Input impedance of probe-excited rectangular microstrip patch radiator

Input impedance of probe-excited rectangular microstrip patch radiator