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Showing papers on "Folded inverted conformal antenna published in 1991"


Proceedings Article
01 Jan 1991
TL;DR: In this paper, the microstrip patches with microstrip transmission delay lines are proposed to form a microstrip reflectarray antenna and the results of a theoretical analysis and evaluation of this antenna are presented.
Abstract: In order for a reflectarray to have a thin flat-plate structure, microstrip patches with microstrip transmission delay lines are proposed to form the microstrip reflectarray antenna. The results of a theoretical analysis and evaluation of this antenna are presented. It is shown that, with proper designs, this antenna can have many significant advantages over a conventional parabolic reflector. >

289 citations


Journal ArticleDOI
TL;DR: A novel antenna structure formed by combining the Yagi-Uda array concept and the microstrip radiator technique is discussed, and experimental results demonstrate the performance of this antenna.
Abstract: A novel antenna structure formed by combining the Yagi-Uda array concept and the microstrip radiator technique is discussed. This antenna, called the microstrip Yagi array, has been developed for the mobile satellite (MSAT) system as a low-profile, low-cost, and mechanically steered medium-gain land-vehicle antenna. With the antenna's active patches (driven elements) and parasitic patches (reflector and director elements) located on the same horizontal plane, the main beam of the array can be tilted, by the effect of mutual coupling, in the elevation direction providing optimal coverage for users in the continental United States. Because the parasitic patches are not connected to any of the lossy RF power distributing circuit the antenna is an efficient radiating system. With the complete monopulse beamforming and power distributing circuits etched on a single thin stripline board underneath the microstrip Yagi array, the overall L-band antenna system has achieved a very low profile for vehicle rooftop mounting, as well as a low manufacturing cost. Experimental results demonstrate the performance of this antenna. >

248 citations


Journal ArticleDOI
TL;DR: In this article, a 2 x 2 dual-polarized microstrip array antenna with high isolation between the two input ports and low crosspolarization level has been developed.
Abstract: A 2 x 2 dual-polarized microstrip array antenna with high isolation between the two input ports and low cross-polarization level has been developed. The technical background for this achievement and antenna performance results are presented.

46 citations


Journal ArticleDOI
TL;DR: In this article, power-induced switching has been observed by Chaloupka et al. in a miniaturized patch antenna, patterned from an epitaxial film of YBa2Cu3O7- delta deposited onto LaAlO3.
Abstract: Power-induced switching has been observed by Chaloupka et al. (1991) in a miniaturized patch antenna, patterned from an epitaxial film of YBa2Cu3O7- delta deposited onto LaAlO3. The antenna is resonant at around 2.3 GHz with a loaded Q of 800 at 77 K and a radiation efficiency of up to 65%. At mean current densities above 2*106 A/cm2 the resonant frequency and Q drop hysteretically, decreasing further with increased current. These effects are attributed to the thermal quenching of weak links present in the inductive section of the antenna.

21 citations


Journal ArticleDOI
TL;DR: A full model is presented of a receiving antenna that includes a microstrip dipole together with its MMIC amplifier that uses the integral equation technique associated with the multiport representation of an active circuit.
Abstract: A full model is presented of a receiving antenna that includes a microstrip dipole together with its MMIC amplifier. The model uses the integral equation technique associated with the multiport representation of an active circuit. Theoretical results are in good agreement with experimental results. Gain and bandwidth are largely increased in comparison to those of the same antenna without an amplifier.

20 citations


Patent
18 Jan 1991
TL;DR: In this paper, a multimode low-profile avionics antenna is disclosed for use in Automatic Direction Finder (ADF) systems, which includes two resonant cavity-backed slot antennas.
Abstract: A multimode low-profile avionics antenna is disclosed for use in Automatic Direction Finder (ADF) systems. The low profile antenna generates a steerable cardioid radiation pattern having a minimum bandwidth of 30% and an unusual degree of independence from mutual coupling and coupling to ground-plane currents. The antenna includes two resonant cavity-backed slot antennas. The upper cavity, which backs a directional crossed-slot antenna, is the larger of the two cavities. The shallow lower cavity is actually a short-circuited radial transmission line employing a stepped inner radius and band-switching to extend the operating bandwidth to the required 30%. The crossed-slot antenna elements are configured orthogonally and the slot ends are folded over the side of the cylindrical cavity to minimize the resonant cavity diameter for the requisite slot length. The slot width is stepped open at the crossover point to enhance antenna bandwidth and to provide for greater spacing between the symmetrically-located feedpoints. The shallow circumferential slot antenna is equipped with two band-switched inductances for wider bandwidth. The two stacked cavities have a combined height of less than 0.1λ at the operating frequency and are suitable for use as a flush-mounted aircraft or helicopter ADF antenna.

18 citations


Proceedings ArticleDOI
24 Jun 1991
TL;DR: In this paper, the authors describe two variations of a novel aperture feeding technique for circularly polarized microstrip antennas, which demonstrate an axial ratio bandwidth of 15% and an impedance bandwidth in excess of 20%.
Abstract: The authors describe two variations of a novel aperture feeding technique for circularly polarized microstrip antennas. Measured results for a series-fed crossed-slot microstrip antenna are shown. Experimental results are shown that demonstrate an axial ratio bandwidth of 15% and an impedance bandwidth in excess of 20%. >

9 citations


Proceedings ArticleDOI
24 Jun 1991
TL;DR: The development of an active integrated antenna utilizing MMIC (monolithic microwave integrated circuit) amplifiers and microstrip transmission lines is presented and the antenna performance is discussed.
Abstract: The development of an active integrated antenna utilizing MMIC (monolithic microwave integrated circuit) amplifiers and microstrip transmission lines is presented. The design procedure is described and the antenna performance is discussed. An active integrated antenna has been verified experimentally. This active antenna configuration has several advantages over the passive configuration in terms of flexibility in size and gain. >

6 citations


Proceedings ArticleDOI
24 Jun 1991
TL;DR: In this paper, a sinuous microstrip antenna was proposed to achieve a performance similar to that of the spiral microstrip antennas over a multioctave bandwidth with polarization diversity.
Abstract: Multioctave microstrip antennas recently developed by the authors (1990) for a spiral geometry have been extended to a sinuous geometry with good performance over a 5:1 bandwidth. The motivation for using the sinuous configuration is to achieve polarization diversity. Dual linear polarizations or dual circular polarizations can be obtained from a single sinuous antenna. Other desirable performance improvements over the loaded-cavity configuration of the sinous antenna, such as that of antenna gain, were also achieved. Measured results are presented which show that the sinuous microstrip antenna is capable of performance similar to that of the spiral microstrip antenna over a multioctave bandwidth with polarization diversity. >

6 citations


Proceedings ArticleDOI
J.A. Navarro1, Kai Chang1, J. Tolleson, S. Sanzgiri, R.Q. Lee 
24 Jun 1991
TL;DR: In this article, a circular patch antenna fed by an aperture coupled microstrip line has been demonstrated, which was enclosed by a cavity to reduce the surface wave interactions in an array environment and to improve heat dissipation when using active devices.
Abstract: A circular patch antenna fed by an aperture coupled microstrip line has been demonstrated. The patch was enclosed by a cavity to reduce the surface wave interactions in an array environment and to improve heat dissipation when using active devices. A pedestal design was also implemented to help heat dissipation when using active microwave circuits. The antenna exhibited a 9.3% bandwidth from 9.55 to 10.48 GHz. >

5 citations


Z. Fan1, J. Huang1
25 Nov 1991
TL;DR: In this paper, an accurate and efficient method for computing the resonant frequencies of an annular-ring microstrip antenna with an air gap is presented, based on Galerkin's method applied in the Hankel transform domain.
Abstract: An accurate and efficient method is presented for computing the resonant frequencies of an annular-ring microstrip antenna with an air gap. The formulation of the problem is carried out rigorously using the full wave analysis. The method of analysis is based on Galerkin's method applied in the Hankel transform domain. The calculated results for the resonant frequencies are presented as a function of the width of the air gap and some are compared with the measured results available in the literature. Excellent agreement between theory and experiment is obtained, and the validity of the present method is confirmed. >

15 Apr 1991
TL;DR: In this article, the design aspects of mutual coupling and coupling mechanisms for window elements were discussed, and the dual band antenna element described by the authors offers a good economy in element packing and an intermediate range of frequency ratios (typically 4:1).
Abstract: The dual band antenna element described by the authors offers a good economy in element packing and an intermediate range of frequency ratios (typically 4:1). Preliminary results on a circularly polarised (CP) probe-fed version of the element indicated good pattern characteristics at both frequencies, though some reduction in bandwidth for the low frequency patch and an increase in mutual coupling for the high frequency elements have been noted. The authors concentrate on the design aspects of mutual coupling and coupling mechanisms for window elements. >


Journal ArticleDOI
TL;DR: In this article, a new microstrip antenna element is described which exhibits polarization agility by employing a T-slot radiator which is driven by the edge fields of a balanced microstrip line.
Abstract: A new microstrip antenna element is described which exhibits polarization agility. This is achieved by employing a T-slot radiator which is driven by the edge fields of a balanced microstrip line. The balanced line can support two propagating modes, namely, an even mode and an odd mode, and by switching between these modes, the orthogonal arms of the T-slot radiator are separately excited thus forming orthogonally polarized radiated fields. A microstrip patch antenna, which displays polarization agility using the same mechanism, is also described.

Proceedings ArticleDOI
24 Jun 1991
TL;DR: In this paper, experimental investigations of the behavior of mutual coupling in cylindrical conformal microstrip antenna arrays and the influence of the conformability of the far-field characteristics for different antenna structures are presented.
Abstract: The authors review experimental investigations of the behavior of mutual coupling in cylindrical conformal microstrip antenna arrays and the influence of the conformability of the far-field characteristics for different antenna structures. The mutual coupling in conformal patch arrays was shown to be weaker than in the planar case. As expected, great interference was found in the shadow region of the cylinder. Measurements show the necessity of the accurate design of conformal patch arrays including mutual coupling. >

Proceedings ArticleDOI
01 Oct 1991
TL;DR: In this article, a multilayer radome not only protects the antenna from hostile environments, but also is designed to sustain aircraft dynamic loading, and the radiating element consists of a planar, dual- flared slot capable of high performance, multioctave operation.
Abstract: The concept for a wideband, embedded/conformal antenna subsystem is presented. A multilayer radome not only protects the antenna from hostile environments, but also is designed to sustain aircraft dynamic loading. The radiating element consists of a planar, dual- flared slot capable of high-performance, multioctave operation. Advanced materials are currently being developed to enhance the low profile and efficient, wideband performance of the radiating element.