scispace - formally typeset
Search or ask a question

Showing papers on "Microstrip antenna published in 2001"


Journal ArticleDOI
TL;DR: This paper presents a novel single-patch wide-band microstrip antenna: the E-shaped patch antenna, where two parallel slots are incorporated into the patch of a micro Strip antenna to expand it bandwidth.
Abstract: This paper presents a novel single-patch wide-band microstrip antenna: the E-shaped patch antenna. Two parallel slots are incorporated into the patch of a microstrip antenna to expand it bandwidth. The wide-band mechanism is explored by investigating the behavior of the currents on the patch. The slot length, width, and position are optimized to achieve a wide bandwidth. The validity of the design concept is demonstrated by two examples with 21.2% and 32.3% bandwidths. Finally, a 30.3% E-shaped patch antenna, resonating at wireless communication frequencies of 1.9 and 2.4 GHz, is designed, fabricated and measured. The radiation pattern and directivity are also presented.

989 citations


Journal ArticleDOI
TL;DR: In this paper, a 1:1.5 VSWR was achieved at operating frequencies around 2 GHz, which is nearly ten times that of a conventional microstrip-line-fed printed wide-slot antenna.
Abstract: Printed wide-slot antennas fed by a microstrip line with a fork-like tuning stub for bandwidth enhancement are proposed and experimentally investigated. Both the impedance and radiation characteristics of this antenna are studied. Experimental results indicate that a 1:1.5 VSWR bandwidth of 1 GHz is achieved at operating frequencies around 2 GHz, which is nearly ten times that of a conventional microstrip-line-fed printed wide-slot antenna. It also achieved a 2-dB gain bandwidth of at least 0.5 GHz.

525 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present some basic rules about electrically small antennas, give clues and guidelines about efficient antenna miniaturization, and, finally, show some examples of miniature antennas developed in their laboratory for practical applications.
Abstract: PCS (personal communication system) devices have become an important part of everyday life. The pressure to design small, lightweight, and user-friendly mobile-communication devices has increased accordingly, creating the need for optimal antennas for mobile applications. In this paper, we present some basic rules about electrically small antennas, give clues and guidelines about efficient antenna miniaturization, and, finally, show some examples of miniature antennas developed in our laboratory for practical applications.

459 citations


Journal ArticleDOI
TL;DR: In this paper, a broadband probe-fed rectangular patch antenna with a pair of wide slits is proposed and experimentally studied, and the proposed antenna can have an impedance bandwidth of about 24%.
Abstract: A new broad-band design of a probe-fed rectangular patch antenna with a pair of wide slits is proposed and experimentally studied. The proposed design is with an air substrate, and experimental results show that, simply by inserting a pair of wide slits at one of the radiating edges of the rectangular patch, good impedance matching over a wide bandwidth can easily be achieved for the proposed antenna. With an air substrate of thickness about 8% of the wavelength of the center operating frequency, the proposed antenna can have an impedance bandwidth of about 24%. For frequencies within the impedance bandwidth, good radiation characteristics are also observed, with a peak antenna gain of about 7.2 dBi.

303 citations


Journal ArticleDOI
TL;DR: A compact integrated antenna that has two feed ports with more than 20 dB isolation between them that can be utilized in compact wireless communication handsets to provide diversity signals or act as a duplexer allowing the receive and transmit signals to be well isolated.
Abstract: We introduce a compact integrated antenna that has two feed ports with more than 20 dB isolation between them. The significance of the design is that it can be utilized in compact wireless communication handsets to provide diversity signals or act as a duplexer allowing the receive and transmit signals to be well isolated. The antenna design is based on merging two patch antennas together in combination with capacitive loading so that a compact design can be obtained. Justification for the design is provided by considering the mutual coupling using the reaction principle and finite-dimensional time-domain (FDTD) simulations. Experimental results are also presented for a design that operates in the 2100-2200 MHz band for possible application in forthcoming third-generation wireless systems. Results include radiation patterns, S-parameters, and signal correlations between ports so that the diversity performance and isolation characteristics of the antenna can be demonstrated. These show that in typical wireless environments envelope cross correlations of less than 0.1 between the ports are obtained.

267 citations


Journal ArticleDOI
TL;DR: In this article, a compact circular-polarization (CP) operation of the square microstrip antenna with four slits and a pair of truncated corners is proposed and investigated.
Abstract: A novel compact circular-polarization (CP) operation of the square microstrip antenna with four slits and a pair of truncated corners is proposed and investigated. Experimental results show that the proposed compact CP design can have an antenna-size reduction of about 36% as compared to the conventional corner-truncated square microstrip antenna at a given operating frequency. Also, the required size of the truncated corners for CP operation is much greater than that for the conventional CP design using a simple square microstrip patch, providing a relaxed manufacturing tolerance for the proposed compact CP design. Details of the experimental results are presented and discussed.

253 citations


Journal ArticleDOI
TL;DR: In this article, a single-feed dual-band circular polarization (CP) radiation was obtained by inserting four T-shaped slits at the patch edges of a square microstrip antenna.
Abstract: New designs of obtaining dual-band circular polarization (CP) radiation of a single-feed square microstrip antenna are proposed and experimentally studied. The proposed single-feed dual-band CP designs are achieved by inserting four T-shaped slits at the patch edges or four Y-shaped slits at the patch corners of a square microstrip antenna. From experiments conducted, a patch size reduction as large as 36% for the proposed design, compared to a conventional CP design without the inserted slits, has been obtained. Details of the design considerations of the proposed antennas are described, and experimental results of the obtained dual-band CP performances are presented and discussed.

237 citations


Journal ArticleDOI
TL;DR: This paper describes the design and testing of a prototype dual-band dual-polarized planar array operating at L- and X-bands, featuring low mass, high efficiency, and limited beam scanning.
Abstract: This paper describes the design and testing of a prototype dual-band dual-polarized planar array operating at L- and X-bands. The primary objectives were to develop new antenna technology with dual-band and dual-polarization capability in a shared aperture, featuring low mass, high efficiency, and limited beam scanning. The design of a prototype planar microstrip array of 2/spl times/2 L-band elements interleaved with an array of 12/spl times/16 X-band elements that meets these requirements is discussed in detail and measured results are presented. The array is modular in form and can easily be scaled to larger aperture sizes.

200 citations


Patent
06 Apr 2001
TL;DR: In this paper, a single or multiple-band antenna assembly for wireless communications devices is presented, which includes a high frequency portion and a low frequency portion, both fed at a common point by a single feed line.
Abstract: A compact single or multiple band antenna assembly for wireless communications devices. One multi-band embodiment includes a high frequency portion and a low frequency portion, both fed at a common point by a single feed line. Both portions may be formed as a single stamped metal part or metallized plastic part. The overall size is suitable for integration within a wireless device such as a cell phone. The low frequency portion consists of two resonant sections which are stagger tuned to achieve a wide resonant bandwidth, thus allowing greater tolerance for manufacturing variations and temperature than a single resonant section, and is useful for single band antennas as well as multi-band antennas where it may be used to enhance bandwidth for both sections of a dual band antenna as well. The resonant sections for single or multi-band antennas operate in conjunction with a second planar conductor, which may be provided by the ground trace portion of the printed wiring board of a wireless communications device. The antenna assembly provides a moderate front-to-back ratio of 3-12 dB and forward gain of +1 to +5 dBi. The front to back ratio reduces the near field toward the user of a hand held wireless communications device, thus reducing SAR (specific absorption rate) of RF energy by the body during transmit. The antenna pattern beam width and bandwidth are increased for a handset during normal user operation, as compared to a half wave dipole.

188 citations


Journal ArticleDOI
TL;DR: In this article, the effects of geometric parameters on the characteristics of the L-probe patch antenna are extensively studied and the variation of input impedance at resonance with different geometric parameters is plotted on a Smith chart.
Abstract: In this paper, the finite-difference time-domain (FDTD) method is employed to analyze L-probe proximity-fed rectangular patch antennas. Numerical results for the input impedance, co- and cross-polarization radiation patterns are presented and compared with the measurements. Good agreement between the computed and measured results is obtained. The effects of geometric parameters on the characteristics of the L-probe patch antenna are extensively studied. For design purposes, the variation of input impedance at resonance with different geometric parameters is plotted on a Smith chart. Mutual coupling between two L-probe patch antennas is also investigated.

187 citations


Patent
12 Jun 2001
TL;DR: In this paper, a first dielectric antenna rod is coupled to a first frequency transmission source for propagating first frequency band radiation from the first fly-by-fly antenna rod into a medium having a medium dielectrics constant.
Abstract: An antenna. The antenna includes a first dielectric antenna rod having a first dielectric constant. The first dielectric antenna rod is coupled to a first frequency transmission source for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant. A second dielectric antenna rod is provided having a second dielectric constant. The second dielectric antenna rod is coupled to a second frequency transmission source for propagating second frequency band radiation from the second dielectric antenna rod into the medium. The first dielectric antenna rod is coaxially mounted within the second dielectric antenna rod. The first dielectric constant is greater than the second dielectric constant. The second dielectric constant is greater than the medium dielectric constant.

Journal ArticleDOI
TL;DR: In this paper, a compact microstrip antenna design is demonstrated by embedding meandering slots in the antenna's ground plane, which can lead to a large antenna size reduction for a fixed frequency operation.
Abstract: A novel compact microstrip antenna design is demonstrated By embedding meandering slots in the antenna's ground plane, it is observed that the resonant frequency of the microstrip antenna is significantly lowered, which can lead to a large antenna size reduction for a fixed frequency operation In addition, enhanced impedance bandwidth and antenna gain are also observed for the proposed antenna Details of the proposed design and experimental results of the constructed prototypes are presented and discussed © 2001 John Wiley & Sons, Inc Microwave Opt Technol Lett 29: 95–97, 2001

Proceedings ArticleDOI
08 Jul 2001
TL;DR: In this paper, the integration and use of RF MEMS switches in microstrip patch antennas and feed structures was investigated for developing reconfigurable multi-band antennas for satellite or UAV-based communications and radar applications.
Abstract: The integration and use of RF MEMS switches in microstrip patch antennas and feed structures were investigated for developing reconfigurable multi-band antennas. The current application focuses on the development of a dual L/X-band antenna that would support several satellite or UAV-based communications and radar applications such as SAR, terrain mapping, GMTI, AMTI, etc. A reconfigurable patch module (RPM) was designed and fabricated consisting of a 3/spl times/3 array of patches connected together using MEMS switches (we simulated MEMS switches with ideal OPEN/CLOSED switches). This RPM could be used as a basic element in a tile/conformal architecture. Stripline power dividers and blind via transitions were developed to demonstrate feed structures that could be located below the radiating aperture.

Journal ArticleDOI
TL;DR: This work calculates the antenna output power correlation and diversity gain under Rayleigh fading conditions and different values of the environment cross-polar discrimination and shows that the aperture coupled patch provides lower output correlation and higher diversity gain than the slanted dipoles in all investigated cases.
Abstract: Dual-polarized antennas are traditionally characterized in terms of port-to-port isolation and co- and cross-polar radiation patterns. For base station antennas in a mobile communications system, the critical parameter is instead the far-field coupling between the two channels. In a mobile communication system, base station antennas with a nominal /spl plusmn/45/spl deg/ to vertical linear polarization are commonly used. Such antennas are difficult to design with constant polarization characteristics in azimuth. We calculate the antenna output power correlation and diversity gain under Rayleigh fading conditions and different values of the environment cross-polar discrimination. Two different antennas are compared: a dual-polarized aperture coupled patch and a slanted dipole configuration, both over an infinite groundplane. We show that the aperture coupled patch provides lower output correlation and higher diversity gain than the slanted dipoles in all investigated cases.

Journal ArticleDOI
TL;DR: In this article, a circular microstrip antenna with dual capacitively coupled feeds for broad-band circular polarization radiation is presented, which can provide an impedance bandwidth (VSWR /spl les/2) of about 49% and a 3-dB axial-ratio bandwidth of about 35%.
Abstract: New design of a circular microstrip antenna with dual capacitively coupled feeds for broad-band circular polarization radiation is presented. The dual feeds are with a small top-loaded disk and are connected to a Wilkinson power divider with a 90/spl deg/ phase shift between its two output feedlines. The radiating circular patch, printed on a thin substrate, is supported by nonconducting posts on a conducting ground plane and is excited capacitively through the dual feeds. With a distance less than 10% times the center operating wavelength between the circular patch and the ground plane, the present proposed antenna can provide an impedance bandwidth (VSWR /spl les/2) of about 49% and a 3-dB axial-ratio bandwidth of about 35%. The antenna gain bandwidth, defined to be within 1-dB gain variation in the axial-ratio bandwidth, is as large as 28%, with the antenna gain level at about 7.0 dBi.

Journal ArticleDOI
TL;DR: In this paper, the impedance of a rectangular patch antenna fed by an inset microstrip transmission line was measured for various feed positions and the dependence found was then compared to theoretical predictions both for this geometry and for the similar case of an INSET coaxial probe feed.
Abstract: The impedance of a rectangular patch antenna fed by an inset microstrip transmission line was measured for various feed positions. The dependence found was then compared to theoretical predictions both for this geometry and for the similar case of an inset coaxial probe feed.

Journal ArticleDOI
TL;DR: In this article, an improved analytical model is presented for calculating the resonant frequency of circular microstrip antennas with and without air gaps, which is widely applicable to all patch diameters-from very large to very small compared to the height of the dielectric medium below the patch.
Abstract: An improved analytical model is presented for calculating the resonant frequency of circular microstrip antennas with and without air gaps. Unlike the previous models, the present one is widely applicable to all patch diameters-from very large to very small compared to the height of the dielectric medium below the patch and also to the substrates covering the entire range of dielectric constants. The computed results for different antenna dimensions and modes of resonance are compared with the experimental values.


Patent
15 Jun 2001
TL;DR: In this paper, a multilayered dielectric substrate is used to improve the efficiency and directivity of an antenna by forming antenna-feeding microstrip lines and ground layers.
Abstract: First to third dielectric layers (201-203) are deposited to form a multilayered dielectric substrate (220). A plurality of conductor patches (204a-204d) are formed on the surface of the first dielectric layer (201). An antenna-feeding microstrip line (205) is formed between the first and second dielectric layers. A ground layer (206) is formed between the second and third dielectric layers (202, 203). Microstrip lines (208a, 208b) for high-frequency circuits are formed on the back of the third dielectric layer (203). The ground layer (206) has a slot (207) though which the antenna-feeding microstrip line (205) and the high-frequency microstrip line (208a) are coupled electromagnetically. Thus, the efficiency and directivity of an antenna are improved.

Journal ArticleDOI
TL;DR: In this paper, the authors describe the development and performance of a wideband dual linear polarization microstrip antenna array used in the Danish high-resolution airborne multifrequency polarimetric synthetic aperture radar, EMISAR.
Abstract: This paper describes the development and performance of a wideband dual linear polarization microstrip antenna array used in the Danish high-resolution airborne multifrequency polarimetric synthetic aperture radar, EMISAR. The antenna was designed for an operating frequency of 1.25 GHz/spl plusmn/50 MHz and was built as an array of 8/spl times/2 probe-fed stacked microstrip patches. The feeding network is constructed in microstrip and is capable of handling 6 kW of peak input-power at an altitude of 45000 ft (unpressurized). The impedance bandwidth (return loss better than -14 dB) of the antenna is 10%, the isolation between the horizontal and the vertical ports of the array is 50 dB and the cross-polarization suppression is 40 dB. A new design principle for simultaneously achieving very low cross-polarization and low side lobes in dual linear polarization antenna arrays has been applied.

Journal ArticleDOI
TL;DR: In this article, a maximum likelihood algorithm is used to minimize the number of measurements, thus reducing the impact on the system and shifting the overhead to a remote site, which reduces the overhead.
Abstract: Calibration of a phased array antenna while the antenna is in service can be a complex and time-consuming procedure that affects use of the antenna and imposes an unacceptable overhead on the system. The procedure described herein uses a maximum likelihood algorithm to minimize the number of measurements, thus reducing the impact on the system and shifting the overhead to a remote site.

Journal ArticleDOI
TL;DR: In this paper, the effect of etched grooves around a patch element has been studied for performance improvement, and effective dielectric constant curves for the shielded micromachined substrates are provided for accurate design of patch antennas.
Abstract: Silicon micromachining has been used to demonstrate the possibility of building high performance microwave and millimeter-wave antennas. To suppress higher order substrate modes and increase the bandwidth of a patch antenna, silicon substrate has been used and material has been selectively removed under the patch area. In addition, the effect of etched grooves around a patch element has been studied for performance improvement, it has been shown that micromachined substrate structure can effectively suppress unwanted surface wave modes resulting in improved radiation efficiency. Moreover, effective dielectric constant curves for the shielded micromachined substrates are provided for accurate design of patch antennas. We have demonstrated that mutual coupling between the radiating patch elements due to surface waves can be controlled using various micromachined substrate configurations.

Patent
26 Jul 2001
TL;DR: In this paper, an artificial anisotropic dielectric material can be used as a microstrip patch antenna substrate, which can be easily designed for the purpose of weight reduction for both linearly and circularly polarized patch antennas.
Abstract: An artificial anisotropic dielectric material can be used as a microstrip patch antenna substrate. The artificial dielectric can be easily designed for the purpose of weight reduction. Preferably, the artificial dielectric is comprised of a periodic stack of low and high permittivity layers. The layers can be oriented vertically below the patch to support electric fields consistent with desired resonant modes. Substrates may be engineered for both linearly and circularly polarized patch antennas. Antenna weight can be reduced to ⅙th up to {fraction (1/30)}th of the original weight using different types of high permittivity layers. This concept has numerous applications in electrically small and lightweight antenna elements such as PIFA antennas. In accordance with one aspect of the invention, the artificial dielectric is comprised of an interlocking structure of low and high permittivity layers for ease of assembly and for overall stability. In accordance with another aspect, the high permittivity layers can be comprised of FSS cards, and can include metallized tabs for further simplification of assembly.

Proceedings ArticleDOI
01 Jan 2001
TL;DR: In this article, a tripleband antenna for GSM/DCS/PCS with a parasitic element to enlarge the bandwidth has been proposed based on the analysis of the board effect on the bandwidth of integrated antennas for mobile phones.
Abstract: Based on the investigation of the board effect on the bandwidth of integrated antennas for mobile phones a concept for a tripleband antenna suitable for GSM/DCS/PCS is developed. The antenna concept comprises a parasitic element to enlarge the bandwidth. The performance of the antenna is analyzed by means of numerical simulations based on the FDTD method.

Patent
31 Jan 2001
TL;DR: In this article, a microstrip antenna (MSA) above a ground plane, having a size corresponding to an operation frequency, at a junction point thereof, electrically connected to one end of a monopole antenna, is used to operate as a complex antenna.
Abstract: A microstrip antenna (MSA) above a ground plane, having a size corresponding to an operation frequency, at a junction point thereof, electrically connected to one end of a monopole antenna having a size corresponding to the operation frequency to operate as a complex antenna. A distance between the feed point of MSA and the junction point determines the input impedance for matching. A microstrip line or an (planer) inverted-F antenna may provide the MSA. The monopole element may be a monopole antenna or helical antenna. A portable wireless communication apparatus includes the antenna apparatus having a housing. The monopole antenna is connected to the MSA when the monopole antenna is extended from the housing. A switch may be provided between the monopole antenna and the MSA for diversity operation. The antenna apparatus may be formed on a Printed circuit board and folded.

Journal ArticleDOI
TL;DR: In this paper, a small and high-directivity antenna based on the Sierpinski fractal is presented, where the unique geometrical properties of fractals have been proven to be useful to design advanced antennas.
Abstract: The unique geometrical properties of fractals have been proven to be useful to design advanced antennas. Enhanced performance in terms of size, gain, or multifrequency behavior is observed in fractal-shaped antennas. Here, a small and high-directivity antenna based on the Sierpinski fractal is presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 239–241, 2001.

Proceedings ArticleDOI
08 Jul 2001
TL;DR: In this article, the FDTD method is applied to analyze probe fed patch antennas and the simulated results agree well with the experimental results of R.P. Jedlicka et al. (see IEEE Trans. Antennas Propagat., vol.29, p.147-9, 1981).
Abstract: Microstrip antenna arrays have found broad applications in recent years and the reduction of mutual coupling is an important criterion in their design. The FDTD method is applied to analyze probe fed patch antennas and the simulated results agree well with the experimental results of R.P. Jedlicka et al. (see IEEE Trans. Antennas Propagat., vol.29, p.147-9, 1981). The mutual coupling of patch antennas on a high dielectric constant substrate, which is of growing interest due to its compact size and conformability with MMIC, is characterized in detail. Such antennas have larger mutual coupling than antennas on a low permittivity substrate because of the pronounced surface waves. The electromagnetic band-gap structure introduced by D. Sievenpiper et al. (see IEEE Trans. MTT, vol.47, p.2059-74, 1999) is then employed to inhibit the surface waves so that the mutual coupling is greatly reduced.

Patent
16 Feb 2001
TL;DR: An antenna system can generate RF radiation fields having dual simultaneous polarization states and having substantially rotationally symmetric radiation patterns, where the beamwidths of respective RF fields for respective radiating elements are substantially equal and are relatively large despite the compact, physical size of the antenna system as discussed by the authors.
Abstract: An antenna system can generate RF radiation fields having dual simultaneous polarization states and having substantially rotationally symmetric radiation patterns The antenna system generates RF radiation patterns where the beamwidths of respective RF fields for respective radiating elements are substantially equal and are relatively large despite the compact, physical size of the antenna system The antenna system can include one or more patch radiators and a non-resonant patch separated from each other by an air dielectric and by relatively small spacer elements The patch radiators and non-resonant patch can have predefined shapes for increasing polarization discrimination The lower patch radiators can be mounted to a printed circuit board that can include an RF feed network and a ground plane which defines a plurality of symmetrically, shaped slots The slots within the ground plane of the printed circuit board can be excited by stubs that are part of the feed network of the printed circuit board The slots, in turn, can establish a transverse magnetic mode of RF radiation in a cavity which is disposed adjacent to the ground plane of the printed circuit board and a ground plane of the antenna system The feed network of the printed circuit board can be aligned with portions of the cavity such that the portions of the cavity function as a heat sink for absorbing or receiving thermal energy produced by the feed network

Journal ArticleDOI
TL;DR: A comprehensive framework to engineering device modeling, which is called generalized space mapping (GSM) is introduced, and four examples of microstrip line, a microstrip right-angle bend, amicrostrip step junction, and a micro Strip shaped T-junction are presented, yielding remarkable improvement within regions of interest.
Abstract: A comprehensive framework to engineering device modeling, which we call generalized space mapping (GSM) is introduced in this paper. GSM permits many different practical implementations. As a result, the accuracy of available empirical models of microwave devices can be significantly enhanced. We present three fundamental illustrations: a basic space-mapping super model (SMSM), frequency-space-mapping super model (FSMSM) and multiple space mapping (MSM). Two variations of MSM are presented: MSM for device responses and MSM for frequency intervals. We also present novel criteria to discriminate between coarse models of the same device. The SMSM, FSMSM, and MSM concepts have been verified on several modeling problems, typically utilizing a few relevant full-wave electromagnetic simulations. This paper presents four examples: a microstrip line, a microstrip right-angle bend, a microstrip step junction, and a microstrip shaped T-junction, yielding remarkable improvement within regions of interest.

Patent
19 Jan 2001
TL;DR: An internal dipole bowtie/meander antenna for a mobile terminal is capable of operating in two distinct RF bands as discussed by the authors, which includes a resonating element and a ground element positioned on opposite sides of a dielectric material.
Abstract: An internal dipole bowtie/meander antenna for a mobile terminal is capable of operating in two distinct RF bands. The antenna includes a resonating element and a ground element positioned on opposite sides of a dielectric material. The dielectric material is positioned generally perpendicular to a ground plane of the antenna. Tuning elements may be added to vary the coupling of the antenna elements to the ground plane.