Showing papers on "Microstrip antenna published in 2000"

Microstrip Antenna Design Handbook

Abstract: Microstrip Radiators: Various Microstrip Antenna Configurations. Feeding Techniques and Modeling. Applications. Radiation Field. Surface Waves and Photonic Band-Gap Structures. Analytical Models for Microstrip Antennas: Transmission Line Model. Cavity Model. Generalized Cavity Model. Multi-port Network Model (MNM). Radiation Fields. Aperture Admittance. Mutual Admittance. Model for Coaxial Probe in Microstrip Antennas. Comparison of Analytical Models. Full-Wave Analysis of Microstrip Antennas: Spectral Domain Full-Wave Analysis. Mixed-Potential Integral Equation Analysis. Finite-Difference Time Domain Analysis.Rectangular Microstrip Antenna: Models for Rectangular Patch Antenna. Design Considerations for Rectangular Patch Antennas. Tolerance Analysis of Rectangular Microstrip Antennas. Mechanical Tuning of Patch Antennas. Quarter-wave Rectangular Patch Antenna. Circular Disk and Ring Antennas: Analysis of a Circular Disk Microstrip Antenna. Design Considerations for Circular Disk Antennas. Semicircular Disk and Circular Sector Microstrip Antennas. Comparison Of Rectangular And Circular Disk Microstrip Antennas. Circular Ring or Annular Ring Microstrip Antenna. Circular Sector Microstrip Ring Antenna. Microstrip Ring Antennas of Non-Circular Shapes. Dipoles and Triangular Patch Antennas: Microstrip Dipole and Center-Fed Dipoles. Triangular Microstrip Patch Antenna. Design of an Equilateral Triangular Patch Antenna. Microstrip Slot Antennas: Microstrip-Fed Rectangular Slot Antennas. CPW-Fed Slot Antennas. Annular Slot Antennas. Tapered Slot Antennas (TSA). Comparison of Slot Antennas with Microstrip Antennas. Circularly Polarized Microstrip Antennas and Techniques: Various Types of Circularly Polarized Microstrip Antennas. Singly-Fed Circularly Polarized Microstrip Antennas. Dual-Orthagonal Feed Circularly Polarized Microstrip Antennas. Circularly Polarized Traveling-Wave Microstrip-Line Arrays. Bandwidth Enhancement Techniques. Sequentially Rotated Arrays. Broad-Banding of Microstrip Antennas: Effect of Substrate Parameters on Bandwidth. Selection of Suitable Patch Shape. Selection of Suitable Feeding Technique. Multi-Moding Techniques. Other Broadbanding Techniques. Multifrequency Operation. Loaded Microstrip Antennas and Applications: Polarization Diversity Using Microstrip Antennas. Frequency Agile Microstrip Antennas. Radiation Pattern Control of Microstrip Antennas. Loading Effect of a Short. Compact Patch Antennas. Planar Inverted F Antenna. Dual-Frequency Microstrip Antennas. Dual-Frequency Compact Microstrip Antennas. Active Integrated Microstrip Antennas: Classification of Active Integrated Microstrip Antennas. Theory and Design of Active Integrated Microstrip Antenna Oscillators. Theory and Design of Active Integrated Microstrip Antenna Amplifiers. Frequency Conversion Active Integrated Microstrip Antenna Theory and Design. Design and Analysis of Microstrip Antenna Arrays: Parallel and Series Feed Systems. Mutual Coupling. Design of Linear Arrays. Design of Planar Arrays. Monolithic Integrated Phased Arrays.

Experimental study of a microstrip patch antenna with an L-shaped probe

Abstract: The L-shaped probe is shown to be an attractive feed for the thick microstrip antenna (thickness around 10% of the operating wavelength). A parametric study on the rectangular patch antenna is presented. It is found that the antenna attains 36% impedance bandwidth (SWR/spl les/2) as well as gain bandwidth and about 7-dBi average gain. A two-element array fed by L-probes is also proposed. Experiments show that the array design can substantially suppress the cross polarization of the proposed antenna. Both the antennas have stable radiation patterns across the passband. Moreover, the measured resonant frequencies of the proposed antenna agree well with an existing formula and the L-probe does not have much effect on the resonant frequency.

A new quasi-Yagi antenna for planar active antenna arrays

Abstract: In this paper, a novel broadband planar antenna based on the classic Yagi-Uda dipole antenna is presented, and its usefulness as an array antenna is explored. This "quasi-Yagi" antenna is realized on a high dielectric-constant substrate, and is completely compatible with microstrip circuitry and solid-state devices. This antenna achieves a measured 48% frequency bandwidth for voltage standing-wave ratio <2, better than a 12-dB front-to-back ratio, smaller than -15 dB cross polarization, and 3-5-dBi absolute gain. Mutual coupling of the antenna in an array environment is investigated. Finally, three simple arrays are presented, demonstrating the usefulness of the antenna as an array element. This novel antenna should find wide application in wireless communication systems, power combining, phased arrays, and active arrays, as well as millimeter-wave imaging arrays.

A broad-band U-slot rectangular patch antenna on a microwave substrate

Abstract: A broad-band U-slot rectangular patch antenna printed on a microwave substrate is investigated. The dielectric constant of the substrate is 2.33. The antenna is fed by a coaxial probe. The characteristics of the U-slot patch antenna are analyzed by the finite-difference time-domain (FDTD) method. Experimental results for the input impedance and radiation patterns are obtained and compared with numerical results. The maximum impedance bandwidth achieved is 27%, centered around 3.1 GHz, with good pattern characteristics.

Multi-mode broadband patch antenna

Abstract: A multi-mode broad band patch antenna is provided that allows for the same aperture to be used at independent frequencies such as reception at 19 GHz and transmission at 29 GHz. Furthermore, the multi-mode broadband patch antenna provides a ferroelectric film that allows for tuning capability of the multi-mode broadband patch antenna over a relatively large tuning range. The alternative use of a semiconductor substrate permits reduced control voltages since the semiconductor functions as a counter electrode.

Compact wideband microstrip antenna with leaky-wave excitation

Abstract: A compact wideband leaky-wave excitation microstrip antenna is provided by a group of microstrip patches disposed on a top region of a dielectric substrate stacked on a conductive ground plane. The top region of the dielectric substrate and the dielectric substrate can be composed of either the same or different dielectric materials. A means for feeding an RF signal, which can be a center feed pin, that normally touches the top conducting patch is electrically isolated from the radiating patches. This arrangement confines the feed current within the probe pin to give an increased input resistance. The compact wideband leaky-wave excitation microstrip antenna permits significant reductions in antenna size, resulting in microstrip antennas with a smaller surface area.

Design and analysis of multisegment dielectric resonator antennas

Abstract: The multisegment dielectric resonator antenna (SDRA) has previously been developed to significantly enhance the coupling to a microstrip line. The MSDRA greatly facilitates the integration with a printed feed distribution network for use in a large array environment. The thickness and permittivity of the dielectric insert of the MSDRA can be adjusted to match the element impedance to that of the feed line. A detailed study of the effects of varying the dielectric insert parameters was carried out and useful guidelines are presented for the design of MSDRAs.

Low cost polarization twist space-fed E-scan planar phased array antenna

Abstract: A polarization twist, space-fed, E-scan planar phased array antenna. The phased array antenna incorporates a polarization twist, space-fed architecture. A plurality of unit cells are formed wherein each cell incorporates a large plurality of phased array elements and associated phase shifters. The space-feed architecture enables 2-bit phase shifters to be employed while still producing low antenna sidelobes. The phased array elements, phase shifters, and associated control circuits for controlling the phase shifters are all preferably formed on one surface of a MMIC substrate. This further simplifies significantly the cost and complexity of manufacturing and testing the E-scan phased array antenna. The antenna can therefore be used in applications where an E-scan phased array antenna would have been too costly to employ. The antenna of the present invention is expected to find particular utility in various radar systems, and more particularly missile defense radar systems where E-scan antennas have traditionally been too expensive to employ.

Slotted rectangular microstrip antenna for bandwidth enhancement

Abstract: With the loading of a pair of right-angle slots and a modified U-shaped slot in a rectangular microstrip patch, novel bandwidth enhancement of microstrip antennas is demonstrated. The required dimensions of the right-angle slots and modified U-shaped slot for bandwidth enhancement with good radiating characteristics have been determined experimentally in this study and the obtained antenna bandwidth can be as large as about 2.4 times that of a corresponding unslotted rectangular microstrip antenna. Details of the antenna design and experimental results are presented and discussed.

Multi-mode patch antenna system and method of forming and steering a spatial null

Abstract: A hand-held antenna specifically for GPS applications is provided which includes a microstrip patch antenna having a ground board, a single radiating patch spaced from the ground board and a resonant cavity defined between the ground board and the single radiating patch. Feed points are provided, one in the geometrical center of the radiating patch, and one, two, or four equidistantly spaced from the central feed point and disposed at 90° angular intervals. A feed network couples fundamental modes of excitation to the side feed points on the patch and a higher mode of excitation to the central feed point. Amplitude and phase controllers are provided in the feed network for amplitude and phase shifting between the fundamental and higher order modes of excitation in order to steer a spatial null in azimuth and elevation.

Single-feed dual-band planar inverted-F antenna with U-shaped slot

Abstract: The development of small integrated antennas plays a significant role in the progress of rapidly expanding wireless communication applications. This paper describes a novel dual-band planar inverted-F antenna (PIFA) for wireless local area network applications. The proposed PIFA uses single feed only. A novel top-plate geometry, a U-shaped slot, is discussed. An example is given for this novel slot shape for frequency bands of 2.4 and 5.2 GHz. Simulation based upon the method of moments (MoM) is used to model the performance of the antenna. Comparisons with results measured on fabricated antenna structures are provided for simulations validation.

A novel photonic bandgap structure for low-pass filter of wide stopband

Abstract: In this letter, a novel photonic bandgap (PBG) structure is proposed for increasing the stopband of a low-pass filter without the increasing circuit size for applications in microstrip circuits The proposed structure is connected in two parallel periodic structures which have a different center frequency of the stopband The wide stopband is achieved by two periodic structures of two different stopbands We also show the performance improvement of microstrip patch antenna by etching of the proposed structure in ground plane

Dual-band dual-polarized perforated microstrip antennas for SAR applications

Abstract: For dual-band dual-polarized synthetic aperture radar (SAR) applications a compact low-profile design is investigated. The operating frequencies are in the L and C-bands, centered about 1.275 and 5.3 GHz, respectively. Since the C-band frequency is larger by a factor of four, its array elements and inter-element separations are smaller by the same ratio. Thus, to allow similar scan ranges for both bands, the L-band elements are selected as perforated patches to enable the placement of C-band elements within them. Stacked-patch configurations were used to meet the bandwidth requirements, especially in the L-band. The C-band element was designed numerically, but the perforated L-band one required final experimental optimization. Also, in the latter case of L-band, a balanced transmission line feed was used to minimize cross polarization. For the C-band elements, slot coupling was used and, to simplify the feed, symmetric parasitic slots were incorporated to minimize cross polarization. No vertical connections were utilized, and electromagnetic couplings resulted in a compact low-profile design, with an electrically and thermally symmetric geometry.

Coaxial dielectric rod antenna

Abstract: An antenna. The antenna (20) includes a first dielectric antenna rod having a first dielectric constant (e3). The first dielectric antenna rod (22) is coupled to a first frequency transmission source (27) for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant (e1). A second dielectric antenna rod (24) is provided having a second dielectric constant (e2). The second dielectric antenna rod is coupled to a second frequency transmission source (28) 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.

Novel millimeter ACC antenna feed

Abstract: In this paper, the author describes the construction and performance of a new microstrip-polyrod antenna feed and compares it to alternative microstrip feeds for dielectric lenses. The antenna feed was developed for an automotive radar system and allows microstrip patch radiators to illuminate dielectric lenses or reflectors in an efficient manner. The antenna feed also has applications in microstrip antenna arrays.

Steerable-beam multiple-feed dielectric resonator antenna of various cross-sections

Abstract: A radiating antenna capable of generating or receiving radiation using a plurality of feeds and a dielectric resonator of various cross-sections is disclosed. The purpose of using multiple feeds with a single dielectric resonator antenna is to produce several beams each having a 'boresight' in a different direction. Several such beams may be excited simultaneously to form a new beam in any arbitrary direction. The new beam may be incrementally or continuously steerable and may be steered through a complete 360 degree circle. The invention may be combined with an internal or external monopole antenna so as to cancel out the antenna backlobe or otherwise resolve the front/back ambiguity that arises with this type of dielectric resonance antenna.

Microstrip tunable filters tuned by dielectric varactors

Abstract: An electronic filter includes a substrate, a ground conductor, an input, an output, a first microstrip line positioned on the substrate and electrically coupled to the input and the output, and a first tunable dielectric varactor electrically connected between the microstrip line and the ground conductor. The input preferably includes a second microstrip line positioned on the substrate and including a portion lying parallel to the first microstrip line. The output preferably includes a third microstrip line positioned on the substrate and including a portion lying parallel to the first microstrip line. The first microstrip line includes a first end and a second end, the first end being open circuited and the varactor being connected between the second end and the ground conductor. The filter further includes a bias voltage circuit including a high impedance line, a radial stub extending from the high impedance line, and a patch connected to the high impedance line for connection to a DC source. In a multiple pole embodiment, the filter further includes additional microstrip lines positioned on the filter substrate parallel to the first microstrip line and additional tunable dielectric varactors electrically connected between the additional microstrip lines and the ground conductor.

Low cost microstrip-fed dual frequency printed dipole antenna for wireless communications

Abstract: A low cost microstrip-fed dual frequency dipole antenna has been developed for personal communication network (PCN) and wireless LAN (WLAN) applications in the 2.4 and 5.2 GHz bands. The antenna radiates bi-directionally and has a double-sided structure to enable transition from a balanced planar stripline to unbalanced microstrip line. The 10 dB bandwidths achieved were 18.75 and 7.7% at 2.4 and 5.2 GHz, respectively.

Electrooptic mapping and finite-element modeling of the near-field pattern of a microstrip patch antenna

Abstract: A comprehensive electrooptic field-mapping technique is applied to the characterization of near-field radiation patterns above a microstrip patch antenna. The amplitude and phase maps of three orthogonal electric-field components, measured using electrooptic crystals above the patch, also have revealed the transition from the near field to the far field of the radiation pattern. In addition, experimental results have been compared with a finite-element method (FEM) simulation. The measurememts show superior results to the FEM simulation, especially in terms of spatial resolution and data acquisition times. Furthermore, the scattering parameter S/sub 11/ for the patch antenna has been calculated from the electrooptic measurement results of standing waves on the feeding line and compared with results from a conventional network analyzer.

Triple band planar inverted F antennas for handheld devices

Abstract: Two novel triple band planar inverted F antennas (PIFAs) are presented. The first antenna is realised by housing a dual frequency L-shaped spur line loaded PIFA element within the lower resonance PIFA element. The second antenna is realised by embedding two single element PIFAs within a quarter-wave patch. For both antennas, an isolation of better than -15 dB between the feed ports and a good agreement between simulation and measurement results was obtained.

Theory of miniaturized shorting-post microstrip antennas

Abstract: An analytical theory for the eigenfrequencies and eigenmodes of shorting-post microstrip antennas (MPA's) is presented. These antennas are seen as promising candidates for miniaturized mobile telecommunication handsets. In particular, it is shown that the zero mode of the unloaded MPA plays a central role for reducing the lowest operation frequency of the loaded MPA. The theory allows a complete calculation of all relevant antenna parameters and can easily be extended to the case of multiple shorting posts. Applications to the examples of rectangular and circular shorting post MPA's are illustrated.

Circular-polarised dielectric resonator antenna excited by dual conformal strips

Abstract: A circular-polarised cylindrical dielectric resonator antenna excited by dual conformal strips is investigated experimentally. The configuration offers a wide axial-ratio bandwidth of 20%. We measured axial ratio, radiation patterns and antenna gain of the configuration are presented and discussed.

Mutual coupling between reduced surface-wave microstrip antennas

Abstract: An investigation of the mutual coupling between reduced surface-wave microstrip antennas is presented and compared with that for conventional microstrip antennas. Numerical results are presented from a theoretical analysis of the mutual coupling along with confirming experimental results. It is shown that for electrically thin substrates, the space-wave coupling, not the surface-wave coupling, is predominant for typical element spacing, for both the conventional and reduced surface-wave antennas. In addition, the mutual coupling behavior is examined using an asymptotic analysis, which demonstrates how the coupling falls off much faster with patch separation for reduced surface wave antennas compared to conventional microstrip patch antennas.

Dual-mode antenna design for microwave heating and noninvasive thermometry of superficial tissue disease

Abstract: Hyperthermia therapy of superficial skin disease has proven clinically useful, but current heating equipment is somewhat clumsy and technically inadequate for many patients. The present effort describes a dual-purpose, conformal microwave applicator that is fabricated from thin, flexible, multilayer printed circuit board (PCB) material to facilitate heating of surface areas overlaying contoured anatomy. Preliminary studies document the Feasibility of combining Archimedean spiral microstrip antennas, located concentrically within the central region of square dual concentric conductor (DCC) annular slot antennas. The motivation is to achieve homogeneous tissue heating simultaneously with noninvasive thermometry by radiometric sensing of blackbody radiation from the target tissue under the applicator. Results demonstrate that the two antennas have complimentary regions of influence. The DCC ring antenna structure produces a peripherally enhanced power deposition pattern with peaks in the outer corners of the aperture and a broad minimum around 50% of maximum centrally. In contrast, the Archimedean spiral radiates (or receives) energy predominantly along the boresight axis of the spiral, thus confining the region of influence to tissue located within the central broad minimum of the DCC pattern. Analysis of the temperature-dependent radiometer signal (brightness temperature) showed linear correlation of radiometer output with test Load temperature using either the spiral or DCC structure as the receive antenna. The radiometric performance of the broadband Archimedean antenna was superior compared to the DCC, providing improved temperature resolution (0.1/spl deg/C-0.2/spl deg/C) and signal sensitivity (0.3/spl deg/C-0.8/spl deg/C//spl deg/C) at all four 500 MHz integration bandwidths tested within the frequency range from 1.2 to 3.0 GHz.

Broadband cross-shaped microstrip-fed slot antenna

Abstract: A cross-shaped microstripline-fed slot antenna of large bandwidth is described. The experimental bandwidth of the antenna is from 1.765 to 4.921 GHz, which is 98.59% for S/sub 11//spl les/-10 dB. The measured radiation pattern of the antenna is also presented.

An internal dual-band mobile phone antenna

Abstract: An internal dual-band mobile phone antenna designed to operate at GSM900 and GSM1800 bands is presented. The antenna is derived from a quarter-wave planar inverted F-type antenna, which has at this state proved to be the most promising candidate for mobile applications due to its compact size and good performance. The FDTD method is used in the study and an experimental verification is also provided.

Semi built-in multi-band printed antenna

Abstract: The present invention provides a miniature, built-in multi-band antenna which is suitable for use in future compact mobile terminals. According to exemplary embodiments, a semi built-in printed antenna is provided which includes patch elements of different sizes and capable of being tuned to different frequency bands. An internal patch element is located on a printed circuit board (PCB) within a communication device and another patch element is located outside the PCB. On each patch element is formed a slot which divides the patch element into sub-parts. Each sub-part of the internal patch element is structured so as to be resonant at a frequency in the same frequency band to which the internal patch element is tuned. Each sub-part of the external patch element is similarly structured but having a resonance with a larger bandwidth than the internal patch element and at a frequency band to which the external patch element is tuned. As a result, a high efficiency, broad band, multi-band, and surface mountable low profile antenna can be realized.

Circularly polarised antenna with switchable polarisation sense

Abstract: The authors present the design of a wideband circularly polarised antenna with switchable polarisation sense. The basic antenna is a circularly polarised aperture coupled patch antenna with a slot excitation located along the diagonal of a rectangular patch. A second slot is added along the other diagonal and beam-lead pin diodes are inserted in both slots to allow a dual sense operation for a compact structure in a 4% CP bandwidth.

A conformal FDTD software package modeling antennas and microstrip circuit components

Abstract: This paper describes a conformal finite-difference time-domain (CFDTD) software package, and presents its applications to RF antennas and microstrip circuit components. The program includes a Visual Basic GUI, for graphically inputting the object geometries, setting source and boundary conditions, generating a non-uniform mesh, and post-processing of the data. A robust CFDTD technique is employed to handle conductors with curved surfaces and edges. Illustrative examples that show the application of the code for modeling antennas as well as microstrip discontinuities are presented in the paper.

Analysis of integrated inverted-F antennas for Bluetooth applications

Abstract: An integrated planar inverted-F antenna (PIFA) is proposed and analyzed. The antenna is printed on the RF printed circuit board of a wireless communication device. Numerical analysis data shows that such an antenna can be utilized with as small as 22 mm by 5 mm by 1 mm of volume. The volume occupancy can be further reduced by adjusting various different antenna parameters. Such guidelines have also been presented. A laboratory prototype of such an antenna has been built and tested. Measured VSWR frequency data show that the antenna has adequate bandwidth within 2:1 VSWR for Bluetooth application. Radiation patterns have been measured in three orthogonal planes of the antenna using both dominant and cross polarizations. Test data demonstrated that the Bluetooth PIFA had comparable performance to a half-wave dipole.