Showing papers on "Patch antenna published in 1987"
TL;DR: In this paper, the effect of anisotropy on the resonant frequency and surface wave excitation of the antenna was considered, and the radar cross section (RCS) was calculated.
Abstract: The problem of a rectangular microstrip antenna printed on a uniaxially anisotropic substrate is treated. The effect of anisotropy on the resonant frequency and surface wave excitation of the antenna is considered, and the radar cross section (RCS) of the antenna is calculated. The RCS calculation includes the effect of the load impedance (antenna mode scattering). Results for the resonant frequency of a patch on a uniaxial substrate are compared with measurements, and the RCS of a patch on an isotropic substrate is compared with measurements. The derivation of the uniaxial Green's function in spectral form, the associated moment method analysis for the input impedance and scattering of the microstrip patch, and the expressions for the far-zone fields of a source on a uniaxial substrate are presented.
367 citations
TL;DR: In this article, the characteristics of a two-layer electromagnetically coupled rectangular patch antenna were investigated for s between 0.31λ0 and 0.37λ0, and the variations of pattern shape, 3 dB beamwidth and impedance bandwidth with spacing s between the two layers were studied.
Abstract: Experimental results on the characteristics of a two-layer electromagnetically coupled rectangular patch antenna are presented. The variations of pattern shape, 3 dB beamwidth and impedance bandwidth with spacing s between the two layers are studied for s between 0 and 0.37λ0. A relatively high-gain region is found for s between 0.31λ0 and 0.37λ0.
325 citations
TL;DR: In this article, a microstrip feedline on a substrate proximity-coupled to a rectangular microstrip patch on a covering superstrate is constructed, and a small open-circuit tuning stub is connected in shunt with the feed line.
Abstract: The letter presents experimental results for a proximity-coupled microstrip patch antenna capable of 13% bandwidth. The impedance match (VSWR ≤ 2), copolarised radiation patterns and crosspolarised radiation were measured over this bandwidth to confirm operation. The construction is quite simple, consisting of a microstrip feedline on a substrate proximity-coupled to a rectangular microstrip patch on a covering superstrate; a small open-circuit tuning stub is connected in shunt with the feed line.
301 citations
TL;DR: In this article, the authors clarified the properties of microstrip-line higher modes in the neighborhood of cutoff and showed that those modes become leaky in that range; with the aid of the steepest-descent plane, one finds that the continuous spectrum can be characterized in a highly convergent manner by essentially a single leaky mode.
Abstract: Some confusion in the literature is clarified regarding the properties of microstrip-line higher modes in the neighborhood of cutoff. It is shown that those modes become leaky in that range; with the aid of the steepest-descent plane, one finds that the continuous spectrum can be characterized in a highly convergent manner by essentially a single leaky mode. The leakage occurs in two forms: a surface wave and a space wave. For structures without a top cover, it is found that almost all of the leakage is in the form of a space wave, so that an efficient leaky-wave antenna of particularly simple configuration may be designed that consists of just a length of uniform microstrip line fed in its first higher mode. An accurate leaky-wave analysis is developed that explains quantitatively the performance features and the limitations of this class of antennas.
260 citations
TL;DR: The pattern averaging gain (PAG) method to estimate the average gain of mobile antennas in a multipath propagation environment is proposed and the antenna configuration with the PIFA element mounted on the lateral side of the radio case is found to be most suitable for portable radio units.
Abstract: The pattern averaging gain (PAG) method to estimate the average gain of mobile antennas in a multipath propagation environment is proposed. By using this method and a wire-grid model, the radiation characteristics of the planar inverted F antenna (PIFA) mounted on a portable radio case is analyzed. In particular, the variation of the antenna gain with the radio case dimensions and inclination angle of the radio case during operation is clarified. Also, the effect on antenna patterns of the operator holding the portable radio is experimentally investigated. Based on this analysis, the antenna configuration with the PIFA element mounted on the lateral side of the radio case is found to be most suitable for portable radio units. In addition, an appropriate selection of the radio case dimensions is found to result in further improvements in the antenna bandwidth.
239 citations
TL;DR: In this paper, a printed circuit antenna element is coupled to a pair of microstriplines on another substrate via two orthogonal, rectangular apertures in a common ground plane.
Abstract: A new method for radiating dual or circular polarisation with a printed circuit antenna element is described. A square microstrip patch on one substrate is coupled to a pair of microstriplines on another substrate via two orthogonal, rectangular apertures in a common ground plane. Quadrature excitation of the system results in circularly polarised radiation.
209 citations
TL;DR: In this paper, a solution to the problem of plane wave scattering by a rectangular microstrip patch on a grounded dielectric substrate is presented, which does not include the so-called "antenna mode" component of the scattering.
Abstract: A solution to the problem of plane wave scattering by a rectangular microstrip patch on a grounded dielectric substrate is presented. The model does not include the microstrip feed, and thus does not include the so-called "antenna mode" component of the scattering. The solution begins by formulating an electric field integral equation for the surface current density on the microstrip patch. The integral equation is solved using the method of moments. Computed data for the patch radar cross section (RCS) is found to be in close agreement with measurements over a broad frequency range. The microstrip RCS versus frequency consists of a number of large peaks which are identified as impedance or pattern factor resonance peaks.
189 citations
TL;DR: In this paper, the radiation pattern of a bow-tie antenna of finite length and infinitesimal thickness, placed on a lossless dielectric substrate, is analyzed based on a representation of the current density on the metal surface of the antenna as a sum of an imposed quasistatic term and a set of current modes with unknown amplitudes.
Abstract: A new formulation is discussed for the rigorous calculation of the radiation pattern of a bow-tie antenna of finite length and infinitesimal thickness, placed on a lossless dielectric substrate. The analysis is based on a representation of the current density on the metal surface of the antenna as a sum of an imposed (quasistatic) term and a set of current modes with unknown amplitudes. Free-space fields that are expressed in terms of continuous spectra of symmetrized plane waves are matched to the current modes using the method of moments. The resulting set of equations are solved for the unknown current amplitudes. The calculations show that for increasing bow length the antenna impedance spirals rapidly to a value predicted by transmission line theory. The theory also shows that the E -plane pattern of a two wavelength, 60\deg bow-tie antenna is dominated by low-loss current modes propagating at the dielectric wavenumber. As the bow tie narrows, the loss of the modes increases, and the dominant wavenumber tends to the quasistatic value. Pattern measurements made at 94 GHz are shown to agree well with theoretical predictions. Measurements for a long-wire antenna, a linear array of bow-tie elements, and a log-periodic antenna are also presented.
173 citations
TL;DR: In this paper, a dual-frequency microstrip antenna consisting of two stacked annular rings of outer radii 5 cm and inner radii 2.5 cm was constructed on a Duroid substrate with relative permittivity 2.32 and thickness 0.159 cm.
Abstract: Experimental results of a dual-frequency microstrip antenna consisting of two stacked annular rings of outer radii 5 cm and inner radii 2.5 cm are presented. Fabricated on a Duroid substrate with relative permittivity 2.32 and thickness 0.159 cm, the separations of the two resonant frequencies range from 6.30-9.36 percent for the first three modes. The frequency separations can be altered by means of an adjustable air gap between the lower ring and the upper substrate.
155 citations
Patent•
10 Dec 1987TL;DR: In this paper, a three resonator capacitively coupled microstrip antenna structure is described, which includes an inverted stacked array of elements with a lowermost driven element directly connected to a transmission line connector.
Abstract: A three resonator capacitively coupled microstrip antenna structure includes an inverted stacked array of elements with a lowermost driven element directly connected to a transmission line connector, and passive elements stacked above the driven element and separated from the driven element and from one another by dielectric layers. The dimensions, spacings and quality factors of the elements are chosen so that at least one, and possibly two elements are resonant at any given frequency within a desired frequency operating range. The resulting antenna structure offers very broad bandwidth at relatively low VSWR in a compact, rugged package. The manner in which parameters of the stacked antenna structure are specified to achieve desired VSWR bandwidth and radiation efficiency is also described.
143 citations
TL;DR: In this paper, a rigorous solution to the problem of a rectangular microstrip antenna fed by a microstripline is presented, where the currents on the feed line and the patch are expanded in a suitable set of modes, and a moment method solution is formulated in the spectral domain.
Abstract: A rigorous solution to the problem of a rectangular microstrip antenna fed by a microstripline is presented. The currents on the feed line and the patch are expanded in a suitable set of modes, and a moment method solution is formulated in the spectral domain. Three special feed cases are treated: a patch fed at a radiating edge; a patch fed at a nonradiating edge; and a proximity coupled patch. Good results are obtained for the radiating edge fed case and the proximity coupled case. The nonradiating edge fed case results were not as good; reasons for this discrepancy are discussed. Calculations are compared with measurements for high and low dielectric constant substrates.
TL;DR: In this paper, the appropriate correction factor to use in the resonant frequency formula of an equilateral triangular patch antenna obtained from the cavity model with perfect magnetic walls is discussed, and the appropriate error correction factor for an EAF with a perfect magnetic wall is discussed.
Abstract: The appropriate correction factor to use in the resonant frequency formula of an equilateral triangular patch antenna obtained from the cavity model with perfect magnetic walls is discussed.
Patent•
16 Nov 1987TL;DR: A compact, easy to manufacture quarter-wavelength microstrip element especially suited for use as a mobile radio antenna has performance which is equal to or better than conventional quarter wavelength whip-type mobile radio antennas as mentioned in this paper.
Abstract: A compact, easy to manufacture quarter-wavelength microstrip element especially suited for use as a mobile radio antenna has performance which is equal to or better than conventional quarter wavelength whip-type mobile radio antennas. The antenna is not visible to a passerby observer when installed, since it is literally part of the vehicle. The microstrip radiating element is conformal to a passenger vehicle, and may, for example, be mounted under a plastic roof between the roof and the headliner.
Patent•
16 Nov 1987
TL;DR: A compact, easy to manufacture quarter-wavelength microstrip element especially suited for use as a mobile radio antenna has performance which is equal to or better than conventional quarter wavelength whip-type mobile radio antennas as discussed by the authors.
Abstract: A compact, easy to manufacture quarter-wavelength microstrip element especially suited for use as a mobile radio antenna has performance which is equal to or better than conventional quarter wavelength whip-type mobile radio antennas. The antenna is not visible to a passerby observer when installed, since it is literally part of the vehicle. The microstrip radiating element is conformal to a passenger vehicle, and may, for example, be mounted under a plastic roof between the roof and the headliner.
Patent•
28 Sep 1987
TL;DR: In this paper, a microstrip probe blade with a metalized ground plane and a straight needle attached to the microstrip axially and protruded from the body parallel to microstrip such that a high frequency signal may be conducted through the device with a minimum of electrical aberations.
Abstract: A microstrip probe blade which has a ceramic body (20) with a microstrip (26) on one side and a metalized ground plane (30) on the other. A straight needle (32) having a tapered end and a spherical tip is attached to the microstrip axially and protrudes from the body parallel to the microstrip such that a high frequency signal may be conducted through the device with a minimum of electrical aberations. With this blade test, frequencies as high as 10 gigahertz may be achieved overcoming previous frequency limitations. The probe blade by virtue of the ground plane (30) wrapping around slightly to the microstrip side of the body (20) allows the addition of resistors (36) or chip capacitors (38) to minimize electrical spikes, transients, and unwanted opscillations to power supply frequencies.
Patent•
31 Jan 1987TL;DR: In this paper, a self-contained sensor module mounted on a power transmission line is used to measure various parameters such as line curvature, voltage, conductor temperature, and ambient temperature.
Abstract: A radiating antenna system for a self contained sensor
module mounted on a power transmission line. The module
is capable of measuring various parameters such as line cur
rent, voltage, conductor temperature, and ambient tem
perature. The parameter values are processed by sensor elec
tronics and the processed values are transmitted to a ground
receiver. The antenna system includes the power transmis
sion line itself, the housing of the sensor module and an im
pedance matching network. The impedance matching net
work couples the output of the transmitter to the housing
which radiates at the operating frequency of the transmitter.
The housing includes apparatus for capacity coupling the hub
of the housing to the transmission line at high frequencies.
15 Jun 1987
TL;DR: In this article, a broadband, contiguous stacked, two-layer, square microstrip patch antenna element design is described which can be used for linear or circular polarization, and the theory is modified to predict radiation patterns and resonant frequencies.
Abstract: A broadband, contiguous stacked, two-layer, square microstrip patch antenna element design is described which can be used for linear or circular polarization. Single layer microstrip patch theory for the rectangular patch radiator is presented and used as a basis for understanding the two-layer patch configuration. The theory is modified to predict radiation patterns and resonant frequencies of the two-layer microstrip patch antenna element. Experimental results include the radiation patterns, dominant resonant frequencies (TM1 0 mode), return loss (S11 ), and bandwidth for X band elements as a function of dielectric constants, dielectric thicknesses, and patch sizes.
TL;DR: In this paper, an algebraic formulation for the resonant frequency of a rectangular microstrip antenna has been derived which is valid for electrically thick substrates and compared with previous theories, as well as actual experimental measurements, for radiators approaching one-quarter wavelength in thickness.
Abstract: An algebraic formulation for the resonant frequency of a rectangular microstrip antenna has been derived which is valid for electrically thick substrates. Predicted values of resonance are compared with previous theories, as well as actual experimental measurements, for radiators approaching one-quarter wavelength in thickness.
TL;DR: In this article, the effect of curvature on the characteristics of a rectangular patch antenna is studied theoretically and experimentally, and it is shown that the pattern broadens, the resonant resistance decreases, the Q-factor is smaller and the bandwidth is larger.
Abstract: The effect of curvature on the characteristics of a rectangular patch antenna is studied theoretically and experimentally. For the TM01 mode it is found that the resonant frequency is not affected by curvature. However, as curvature increases the pattern broadens, the resonant resistance decreases, the Q-factor is smaller and the bandwidth is larger. Good agreement between theory and experiment is obtained.
Patent•
09 Sep 1987
TL;DR: In this paper, a circularly polarised antenna including first and second multiple patch antenna structures is described, each antenna structure consisting of four shorted patches, the patches of both structures being disposed in the planes of the patches so that the radiating edges of the two patch structures form superimposed antenna structures.
Abstract: A circularly polarised antenna including first and second multiple patch antenna structures dimensioned to operate at two distinct frequencies, each antenna structure consisting of four shorted patches, the patches (11a) of the first structure being spaced from a ground plane (10) by dielectric material (12), the patches (14a) of the second structure being spaced from the patches of the first structure by dielectric material (13), the patches of the second structure each overlying a corresponding patch of the first structure and each having a dimension λm (2)/4 which is less than the dimension λm (1)/4 of the corresponding patch of the first structure, with feed means (16a, 17a) for each of the patches, the patches of both structures being disposed in the planes of the patches so that the radiating edges of the two patch structures form superimposed antenna structures.
Patent•
01 Jul 1987TL;DR: In this paper, a microstrip groundplane conductor is split into two balanced ground arms at one end, and a unique microstrip excitation structure is placed above the split ground elements on the opposed surface of the substrate to excite the antenna.
Abstract: An balun/antenna apparatus is provided which is capable of being fabricated on a printed circuit board substrate by automated equipment. The balun-antenna includes a microstrip groundplane conductor which is split into two balanced ground arms at one end. The split groundplane conductor operates as both a balun and as a radiating conductor. A unique microstrip excitation structure is situated above the split ground elements on the opposed surface of the substrate to excite the antenna with radio frequency energy.
TL;DR: In this article, a new feeding configuration for microstrip antennas is described, where separate substrates are used for the radiating patch element and the microstrip feedline, and the patch is excited through an aperture in the antenna substrate ground plane by proximity coupling to the micro strip feedline.
Abstract: A new feeding configuration for microstrip antennas is described, where separate substrates are used for the radiating patch element and the microstrip feedline. The substrates are joined perpendicular to each other, and the patch is excited through an aperture in the antenna substrate ground plane by proximity coupling to the microstrip feedline, This design thus has a number of advantages over other feeding configurations, particularly when used in an integrated phased array application. These features, as well as the measured results from two experimental models, are described.
Patent•
13 Oct 1987
TL;DR: In this article, a microstrip antenna includes an annular conducting element spaced by a dielectric element from a conducting ground plane and radiating circular polarization in a conical elevation pattern.
Abstract: A microstrip antenna includes an annular conducting element spaced by a dielectric element from a conducting ground plane and radiating circular polarization in a conical elevation pattern. A central whip antenna may be located on the axis of the annular-shaped element. Another microstrip antenna having an annular conducting element may be dielectrically spaced from the first-mentioned annular conducting element that comprises the ground plane for the second annular-conducting element.
Patent•
20 Apr 1987
TL;DR: An antenna for mounting on a nonconductive surface such as a windshield of an automobile coupled by a capacitor to housing on the inside of the resonant plate is described in this article.
Abstract: An antenna for mounting on a non-conductive surface such as a windshield of an automobile coupled by a capacitor to housing on the inside of the resonant plate. The antenna has a jack for receiving a plug from a car radio and provides for interchangeability of the cable between the radio receiver and the jack. The circuit allows for fine tuning to the resonant frequency of the antenna.
Patent•
14 Dec 1987
TL;DR: In this article, a foreshortened log-periodic antenna with various configurations of dipole elements and a tapered feedline is described. But the antenna is not considered in this paper.
Abstract: A foreshortened log-periodic antenna which includes variously configured dipole elements and a tapered feedline is disclosed. The dipole elements are arranged in four regions. A first region, located nearest to a feed end of the antenna, includes solid triangular dipoles having constant base-to-height ratios. A second region, adjacent to the first region, includes solid triangular dipoles having decreasing base-to-height ratios. A third region, located adjacent to the second region, includes a single linear dipole. A fourth region, located adjacent to the third region and nearest to a low frequency end of the antenna, includes foreshortened dipoles. The feedline may be implemented either in coaxial or microstrip form so that a lower characteristic impedance is pressed at the feed end of the antenna than at the low frequency end of the antenna. Specifically, for a coaxial feedline having individual conductors separated by a distance "d" at the feed end of the antenna, the individual conductors taper relative to each other so that they are separated by a distance of 2d-5d at the low frequency end of the antenna.
Patent•
15 Sep 1987TL;DR: In this article, a planar antenna is described which comprises a sandwich-like structure of a radiating patch, ground plane and transmission feed line, and the energization of the feed line excites radiating modes in both the aperture and the space between the radiating patches and ground plane, resulting in an improved impedance bandwidth.
Abstract: A planar antenna is described which comprises a sandwich like structure of a radiating patch, ground plane and transmission feed line. Capacitive means connect the path to the feed line through a rectangular aperture in the ground plane. The energization of the feed line excites radiating modes in both the aperture and the space between the radiating patch and ground plane thereby resulting in an improved impedance bandwidth.
15 Jun 1987
Patent•
19 May 1987
TL;DR: In this article, the authors proposed a multi-path processing unit to prevent the transmission band width from being made broader than the signal band by radiating a modulation wave from the 1st transmission antenna, retarding the modulation wave by one time slot or over from the 2nd transmission antenna and providing a multihop processing unit extracting a main wave component included in a received wave to the receiver side.
Abstract: PURPOSE: To prevent the transmission band width from being made broader than the signal band by radiating a modulation wave from the 1st transmission antenna, radiating a delayed wave retarding the modulation wave by one time slot or over from the 2nd transmission antenna and providing a multi-path processing unit extracting a main wave component included in a received wave to the receiver side. CONSTITUTION: A transmission code series is inputted to a modulator 9, the modulation output is radiated directly from a transmission antenna 10, converted into a delay modulation wave retarded by one time slot or over (Td) by a delay circuit 11 and radiated from a transmission antenna 12. A signal wave received by a reception antenna 13 is the synthesis of the signal from the transmission antenna 10 and the signal from the transmission antenna 12, and the transmission antennas 10, 12 are located with a proper distance so that the correlation between both the waves is nearly 0 at the receiving point. The received synthesis wave is amplified by a receiver 14, detected by a detector 15 and the main wave is emphasized and extracted by a waveform equalizer 16 as a multi-path processing unit and the component other than the main wave is cancelled. COPYRIGHT: (C)1988,JPO&Japio
Patent•
17 Mar 1987
TL;DR: In this paper, a high frequency amplifier is mounted in the immediate vicinity of a feeder of a microstrip antenna, which is used to reduce disturbances caused by external noises and improve the noise figure of a receiving equipment.
Abstract: A high frequency amplifier is mounted in the immediate vicinity of a feeder of a microstrip antenna. A microstrip antenna includes a dielectric member and a grounded conductor member which is applied thereto. A second dielectric member is disposed on the side of the grounded conductor member which faces away from the dielectric member, and the high frequency amplifier is mounted on the surface of the second dielectric member which faces away from the grounded conductor member, and is connected to the feeder of the microstrip antenna. A transmission distance between the feeder and the high frequency amplifier, which represents an initial amplifier stage, is greatly reduced, thus drastically reducing disturbances caused by external noises and improving the noise figure of a receiving equipment.