Showing papers on "Microstrip antenna published in 1996"

A circularly polarized small-size microstrip antenna with a cross slot

Abstract: An antenna with a low profile, small size, and a light weight is required in mobile satellite communications. A new, circularly polarized small-size microstrip antenna using a proximity coupled feed method is proposed. A simple configuration based on a cross slot with unequal slot lengths on a circular patch is adopted to realize a small-size element antenna. The proposed antenna has no 90/spl deg/ hybrid coupler for circular polarization. The measured results verify the circular polarization, and the antenna radius was reduced by about 36% by using the slot lengths which are nearly equal to the diameter of the circular patch antenna. Good impedance and axial ratio characteristics have been obtained.

Flat lens antenna concept using aperture coupled microstrip patches

Abstract: A planar lens antenna based on aperture coupled microstrip patch elements with stripline delay lines is described. Features of this design are discussed, and results for transmission coefficient magnitude against frequency are presented. The background for the development of this lens configuration is discussed in terms of a natural progression from frequency selective surfaces, and the inadequacies of simpler geometries are explained.

CAD of microstrip antennas for wireless applications

Abstract: From the Publisher: The recent explosion in commercial applications involving RF and microwave systems (e.g. mobile telephones) is fueling customer demand for small, low-cost, easy-to-use systems. It's also driving innovations in antenna technology. This "how-to" book explains why microstrip antennas are the ideal low-profile, low-cost solution for these commercial applications and provides the information and tools necessary to design them. Included are: • A brief description of microstrip antennas, pertinent terminology, plus analysis and modeling techniques to sharpen your insight into the operation of various elements and arrays • Step-by-step coverage of the design of various single-element radiators, including rectangular, circular, broadband, and CP patches. Interaction between design parameters and antenna performance is also discussed • An in-depth explanation of simple array design, including performance and calculations, types of array architectures, and specific design aspects • Discussion of advanced feeding techniques that provide increased design flexibility and performance This book comes bundles with an IBM PC-compatible diskette containing 18 stand-alone computer programs and a user-friendly guide showing sample design cases and expected results to assist in the analysis and design of specific microstrip antennas and arrays. The design approaches, techniques, and nearly 280 equations presented here are essential information for design engineers and engineering managers involved in the design of antennas and RF/microwave circuits. This technical reference helps you develop an intuitive understanding of microstrip antenna operations - andmaster the steps necessary to create more effective designs. Product line managers and marketing managers also find this information valuable when assessing the applicability of microstrip antennas in current and future product lines.

A planar dual-frequency array antenna

Abstract: A dual-frequency array antenna having an essentially planar structure with electronic beam steering capability in both a low and high frequency band independently of each other, constructed, in a layered formation, from a top planar array antenna unit operating in the low frequency band and a bottom planar array antenna unit operating in the high frequency band. The top planar array antenna is transparent to frequencies in the high frequency band.

Stacked microstrip antenna with wide bandwidth and high gain

Abstract: A stacked microstrip antenna with two parasitic elements, one of which increases the impedance bandwidth and the other which enhances the gain, has been investigated experimentally. The effects of each parasitic element have been clarified as well as the characteristics of the stacked three-element antenna and the design procedure for the stacked microstrip antenna have been described.

Experimental demonstration of a phased-array antenna optically controlled with phase and time delays

Abstract: The experimental demonstration and the far-field pattern characterization of an optically controlled phased-array antenna are described. It operates between 2.5 and 3.5 GHz and is made of 16 radiating elements. The optical control uses a two-dimensional architecture based on free-space propagation and on polarization switching by N spatial light modulators of p × p pixels. It provides 2N−1 time-delay values and an analog control of the 0 to 2π phase for each of the p × p signals feeding the antenna (N = 5, p = 4).

Compact microstrip patch antenna

Abstract: This article describes the design and development of a relatively compact microstrip patch antenna. At resonance, the length of the antenna is approximately one-eighth of the effective wavelength. The current distribution on the patch surface has been analyzed with the use of the method of moments. © 1996 John Wiley & Sons, Inc.

Ring shaped antenna

Abstract: An antenna for broadcasting omnidirectionally is disclosed. The antenna includes a cylindrical housing which has a lip which includes slots adapted to receive a patch antenna strip and a conductive ring. A GPS receiver and electronics package may be placed in the center of the housing. The patch antenna strip which includes a number of patch antennas broadcasts and receives radio signals. The conductive ring absorbs energy broadcast from the patch antennas and rebroadcasts the signal omnidirectionally. The resulting signal has a high gain and a wide bandwidth. A third embodiment in which the conductive ring is incorporated into a housing cover is also disclosed. The antenna is easily and inexpensively assembled and is more durable and reliable than prior art antennas.

Antenna array in an RFID system

Abstract: In accordance with the present invention, a general antenna system is disclosed suitable for applications in which an RFID Tag passes by an Interrogator. We then disclose a specific antenna design that uses a single planar antenna for transmit and a multi-element planar antenna array for receive. The multi-element planar antenna array is spaced such that each of the planar elements is four inches apart, center-to-center, thus defining a narrow 30° receive beamwidth in the horizontal plane. The vertical receive bandwidth is much greater than 30°, facilitating the Interrogator receiving signals at a variety of elevations. Furthermore, a multi-way microstrip combiner is used to sum the signals received from each of the planar antennas. To block interference from the transmit antenna and to improve receive sensitivity, this multi-way microstrip combiner is shielded using, in one embodiment, copper tape along its edges. In a specific embodiment, a four element receive antenna design is disclosed.

Multiband phased-array antenna with interleaved tapered-elements and waveguide radiators

Abstract: Multiband, multibeam, phased array antennas are required for today's multi-function radar and communication applications. These types of antennas play a major role in the shipboard and airborne environment, where space is limited. A single antenna is now asked to perform multiple functions, including long-range surveillance, navigation, weapons control, tracking and recognition, and electronic warfare support measures. A phased array antenna capable of covering several different frequency bands in a common aperture is highly desirable, and is currently being pursued for many of these applications. A number of multiband radar antenna configurations have been proposed in the past. An ultra-wideband phased array antenna design using interleaved waveguide elements and wideband tapered elements is presented. This phased array antenna can operate over at least three frequency bands. Numerical results of the aperture match for both types of radiators, including mutual interaction, are presented.

Improved coupling for aperture coupled microstrip antennas

Abstract: Aperture shape and size are the crucial parameters for the aperture coupled microstrip antennas (ACMSA). A systematic comparision of various aperture shapes for the aperture coupled rectangular microstrip antenna has been carried out. An optimum "hour glass"-shaped aperture configuration has been proposed for maximum coupling.

Analysis and design of feeding structures for microstrip leaky wave antenna

Abstract: Three arrangements of the feeding structure for the excitation of a microstrip leaky wave antenna are proposed and investigated in this paper. A full-wave spectral domain integral equation method combined with the fundamental mode sampling technique is applied to determine the reflection coefficient of the excitation source. Tabulation technique is used to reduce the computational effort. Dependence on structural parameters such as line width, line spacing and overlap length is fully analyzed to obtain the design criteria for a microstrip leaky wave antenna. Additionally, an experimental setup is used to check the validity of our numerical results and verify the radiation nature of the microstrip line first higher-order mode.

A small microstrip patch antenna with a convenient tuning option

Abstract: The paper addresses two aspects of resonant microstrip patch antennas, namely, miniaturization and resonant frequency tuning. First, a patch geometry which allows a controllable size reduction over a limited range is presented. The basic shape is circular with slits cut into it. Modification of the slit geometry leads to both linear as well as circular polarized (CP) operation. Second, the use of another patch of a specific shape as a superstrate layer in a stacked configuration allows tuning over a relatively large frequency range as compared to the patch bandwidth. Tuning is accomplished by a simple rotation of the superstrate layer. The use of another superstrate layer allows tunable CP operation. Details on the antenna characteristics have been worked out for two examples, and computations have been compared with measurements where possible. Some design guidelines have also been included.

New compact microstrip antenna

Abstract: A new microstrip antenna geometry with considerable reduction in size, with similar radiation characteristics to those of an equivalent rectangular patch antenna is proposed. A relationship has been suggested for finding out the resonant frequency of the new geometry, and its validity has been established by the experimental results. Without increasing the aperture area, this geometry also offers a facility for considerably reducing the resonant frequency compared to conventional patches.

A simple feed model that reduces time steps needed for FDTD antenna and microstrip calculations

Abstract: The finite-difference time-domain (FDTD) method is being widely applied to antenna and microstrip calculations. One aspect of this application is accurately and efficiently modeling antenna and microstrip feeds within the constraints of the FDTD approximations. Several relatively straightforward approaches have been suggested, including gap and frill feeds. More complicated approaches, which involve including the coaxial feed cable in the FDTD calculation space, have also been suggested. A related aspect is the desirability of reducing the number of time steps required for the FDTD calculations to converge, especially for transient excitation. We illustrate that for many geometries a simple gap model with an internal source resistance provides accurate results while greatly reducing the number of time steps required for convergence.

Input impedance of aperture-coupled dielectric resonator antennas

Abstract: Dielectric resonator antennas (DRA?s) excited by a narrow-slot aperture in a conducting ground plane are analyzed using a numerical technique based upon a surface-integral equation formulation for bodies of revolution (BOR's) coupled to non-BOR geometries. An efficient matrix-solution algorithm, together with a simple microstrip transmission-line model or a delta-source model are used to comnute the antenna inmt impedance. Input impedances obtained with this technique show favorable agreement to those obtained via another numerical technique, as well as to those obtained by measurement.

Wideband aperture coupled stacked patch antenna using thick substrates

Abstract: An aperture coupled stacked patch microstrip antenna is presented which is capable of operating over a bandwidth in excess of 50%. Measured and predicted impedance behaviour and gain over the band are given. Other important factors such as surface wave efficiency and back radiation levels are presented.

Heterogeneous multi-lamination microstrip antenna

Abstract: A multifrequency-band microstrip antenna, for use in microwave to millimeter-wave band, is provided with different thicknesses of dielectric films to optimized the performance in any operating frequencies desired. In a double lamination antena substrate, for example, lamination 1 is made up of a number of dielectric films having a given dielectric constant and thickness, and lamination 2 is made up of a number of dielectric films of another given dielectric constant and thickness. An radiation element is provided between the films in lamination 2 , and a ground plane is provided between the films in lamination 1 . A strip conductor for propagating radio signals is provided in lamination 1 such that the ground plane intervenes between the radiation element and the strip conductor, thereby shielding the radiation element except for a slot formed in the ground plane. The input signal couples to the radiation element through the slot, thereby feeding the radiation element and operating the microstrip antenna.

Dual-band antenna for hand held portable telephones

Abstract: A novel planar dual-band inverted F-antenna for hand held portable telephones has been realised to operate at 0.9 and 1.8 GHz bands. The dual-band antenna is almost the same size as a conventional inverted F-antenna operating at 0.9 GHz, and has an isolation between bands of better than 17 dB.

Antenna system for radio signals in at least two spaced-apart frequency bands

Abstract: In an antenna system for radio signals in at least two spaced-apart frequency bands above 200 MHz, a quadrifilar helical antenna having an elongate dielectric core with a relative dielectric constant greater than 5 has a conductive sleeve surrounding a proximal part of the core and a longitudinal feeder structure extending through the core to a connection with the helical antenna elements at a distal end of the core. The antenna is operated in an upper frequency band in which it exhibits a first mode of resonance characterized by current maxima at the connections of the helical elements to the feeder structure and at their junctions with the rim of the sleeve, and in a lower frequency band in which the antenna exhibits a second mode of resonance characterized by current minima in the region of the junctions of the helical elements and the sleeve rim. To permit dual mode operation, the antenna system includes an impedance-matching diplexer having filters coupled between a common port for the antenna and further ports for connection to radio signal processing equipment such as a GPS receiver and a mobile telephone operating in the two frequency bands. In the preferred embodiment, the filters and impedance matching elements are formed as microstrip elements on a single substrate.

The resonant frequency of rectangular microstrip antenna elements with various substrate thicknesses

Abstract: Formulas based on transmission-line, cavity, and magnetic-wall models to determine the resonant frequencies of a rectangular microstrip antenna element have been studied and their validity assessed. Their variations were experimentally verified by analyzing a set of newly designed antenna elements with substrates satisfying the criteria h ≤ 0.0815λ0 for 2.22 ≤ ϵr ≤ 10.2, where λ0 is the free-space wavelength, h the thickness, and ϵr the relative permittivity of the dielectric substrate. © 1996 John Wiley & Sons, Inc.

Oscillator-type active-integrated antenna: the leaky-mode approach

Abstract: This paper describes basic research carried out to design a microwave source module employing the concept of an active-integrated leaky-mode antenna. The novel active-antenna source module utilizes a microstrip as the radiating element while adopting uniplanar technology for the active circuit design. The microstrip is operated in the first higher order odd mode, which is a leaky mode, and excited by a proximity-coupled center-fed slotline on the same surface of the uniplanar microwave-integrated circuit. The measured performance of an X-band transmission-type injection-locked active-integrated antenna source module demonstrated that such a design approach was suitable for linear array integration for quasi-optical power combining. The harmonic-balance (HB) analysis of the proposed active-integrated antenna agrees with the measurements in both free-running frequency and power level. The measured radiation patterns of the active-integrated antenna also agree well with the theoretical predictions.

A single-layer dual-frequency rectangular microstrip patch antenna using a single probe feed

Abstract: A simple design of a dual-frequency microstrip antenna using a single rectangular patch and a single probe feed is described. Experimental results of the antenna resonating at frequencies of about 1.42 and 1.54 GHz are presented. Measurements are verified by the theoretical results obtained from full-wave solutions. © 1996 John Wiley & Sons, Inc.

Design of a dual frequency reflectarray using microstrip stacked patches of variable size

Abstract: A new stacked microstrip reflectarray, based on patches of variable size, is proposed for dual frequency operation A progressive phase distribution is achieved for the reflected wave at both frequencies by adjusting the resonant length of the patches in each elementary cell of the reflectarray

An investigation of a novel broadband dielectric resonator antenna

Abstract: Recently, dielectric resonator antennas (DRA) have been proposed as an alternative to the popular microstrip patch. Since then, research has continued, extending their performance capabilities and confirming their potential as low profile and efficient antenna elements for array applications. Also a single-point fed dielectric resonator antenna has been reported, capable of radiating a circularly polarized signal with a much wider axial ratio bandwidth than a similar single-point fed microstrip patch. Further capability enhancements of a dielectric resonator antenna have recently been demonstrated by fabricating the antenna from ferrite material. With a properly biased static magnetic field, it has been shown to possess frequency tuning and polarization diversity properties. The purpose of this paper is to present a novel development of a DRA which possesses a much wider operational bandwidth than previously reported. This improvement can be accomplished with a simple slot feed and without an elaborate matching circuit or a complicated stacking procedure which is generally required by the microstrip patch.

Performance of a cross-aperture coupled single feed circularly polarised patch antenna

Abstract: A novel method for radiating circular polarisation (CP) with a patch antenna without an external polariser has been investigated. It has the advantage of improving the axial ratio bandwidth for single feed CP antennas by using a thick air substrate and inverted patch configuration.

Microstrip antenna device

Abstract: In a microstrip antenna device which has a radiating patch 11 and a ground plate disposed opposite and in parallel to each other, a metal plate 21 is provided on the ground plate in the vicinity of at least one of opposite marginal edges of the radiating patch 11 in the direction of resonance to form an additional capacitance between an open end of the radiating patch in the direction of resonance and the ground plate, thereby permitting reduction of the antenna length.

Parasitic coplanar three-element dielectric resonator antenna subarray

Abstract: A slot-coupled rectangular dielectric resonator antenna in the parasitic coplanar configuration is investigated experimentally. The measured results for impedance and radiation patterns are presented for the three-element case. It is found that by using suitable choice of the dimensions and offset distance of each dielectric resonator, the impedance bandwidth can be as high as three times that of the single-element structure.