Abstract: A microstrip antenna has first and second cylindrically-shaped dielectric layers having first sides secured together with an array of conducting strips conformally interposed therebetween, the strips being spaced to define a slot between each pair of adjacent strips. A conductive ground plane is disposed on an interior second side of the first dielectric layer, and an array of spaced apart radiating patches are conformally disposed on an exterior second side of the second dielectric layer, each of which patches is positioned over a corresponding slot. Responsive to electromagnetic energy, a high-order standing wave is induced in the antenna and a directed beam is transmitted from and/or received into the antenna.

Abstract: An apparatus and method to reduce the size of a microstrip antenna without sacrificing antenna efficiency too much are described. The antenna structure includes discontinuity of strip width in the middle of the antenna patch to reduce the size of the antenna at a given resonant frequency. The antenna structure further includes a plurality of patches of differing widths connected to each other at junctions. The junctions are placed symmetrically to ensure maximum radiation at the boresight and also to further reduce cross-polarization levels. A coaxial feed is connected at a predetermined location near the center of a patch, having a narrower width, in order to match the input impedance of the antenna to the coaxial feed.

Abstract: A first and a second conductive patch of a compact cylindrical microstrip antenna are connected at a junction point to shorten the length of the impedance transition from one edge, where the wave impedance vanishes, to the other patch edge, where the impedance becomes very large. The second conductive patch is wider than the first conductive patch and one end of the first conductive patch is shorted with the ground plane. The effective impedance to be satisfied by the narrower strip at the junction is greatly reduced by the presence of the junction of two different patches, which substantially decreases the size of the antenna at a given operation frequency.

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.

Abstract: A microstrip antenna providing circularly polarized radiation formed by two layered cavities with two rectangular conductive patches. A first cavity s formed by a ground plane and a first rectangular conductive patch having a lateral dimension and coupling holes placed therein. A second cavity is formed between the first rectangular conductive path and a second rectangular conductive patch having a longitudinal dimension. The longitudinal dimension of the second rectangular conductive patch is essentially equal to the lateral dimension of the first rectangular conductive patch. The second rectangular conductive patch is coupled through the coupling holes to the first rectangular conductive patch, resulting in circularly polarized radiation. The circularly polarized antenna can easily be manufactured using conventional microstrip techniques. Additionally, bandwidth and power are improved.

Abstract: A microstrip antenna has two dielectric layers bonded together with an array of conducting strips interposed therebetween, the strips being spaced to define a slot between each pair of adjacent strips. A conductive ground plane is disposed on a first outer side of the two bonded dielectric layers, and an array of radiating patches are disposed on a second outer side of the two bonded dielectric layers, each of which patches is positioned over a corresponding slot, the array of patches being spaced apart to form an aperture between each pair of adjacent patches. Responsive to electromagnetic energy, a high-order standing wave is induced in the antenna and a directed beam is transmitted from and/or received into the antenna.

Abstract: A wideband leaky-wave microstrip antenna having two elongated rectangular nductive patches separated by a gap on a first dielectric material and an elongated rectangular conductive coupling patch on a second dielectric material placed over the gap. The selective placement of the conductive patches and the gap formed thereby permits impedance matching resulting in a leaky-wave propagation mode. Non-radiating modes of propagation are not excited, thereby enhancing the leaky-wave mode of propagation causing radiation. This results in a relatively wide bandwidth of operation that has a main beam that is scannable as a function of frequency. The bandwidth increases substantially as the dielectric constant approaches one. The planar construction contributes to design flexibility and ease of manufacture and has many applications military and commercial communication systems.

Abstract: A microstrip antenna has two dielectric layers bonded together with an array of conducting strips interposed therebetween, the strips being spaced to define a slot between each pair of adjacent strips. A conductive ground plane is disposed on a first outer side of the two bonded dielectric layers, and an array of radiating patches are disposed on a second outer side of the two bonded dielectric layers, each of which patches is positioned over a corresponding slot, the array of patches being spaced apart to form an aperture between each pair of adjacent patches. Responsive to electromagnetic energy, a high-order standing wave is induced in the antenna and a directed beam is transmitted from and/or received into the antenna.

Abstract: A phase shifter transmission line includes a semiconductor layer 20; a first conductor region 42 on the semiconductor layer 20; a first doped region 24 and 30 in the semiconductor layer adjacent the first conductor region; and a variable bias voltage coupled to the first conductor region 42 for varying an effective dielectric constant in the transmission line.

Abstract: A circularly polarized antenna is described having a ground plane and spa conductive patches parallel to it forming lower and upper cavities. The lower cavity is excited by a coax introduced at an impedance matching point in the ground plane, and the upper cavity is energized by apertures in the middle patch. The sides of the lower cavity from which radiation does not emanate are shorted to the ground plane, and the sides of the upper cavity from which radiation does not emanate as shorted to the middle patch.

Abstract: A planar dual band antenna comprising three superimposed dielectric layers, ground plane on one external surface, a conductive patch on the other and parallel conductive strips at the interface of dielectric layers that is closer to the patch. The dielectric constant of the middle layer is different from that of the two other layers.