Abstract: A dual band, stacked microstrip antenna produces circular polarization. A two-layer, 90.degree. microstrip coupler is mounted to a hi-band patch and a lo-band patch and provides two inputs to the antenna to excite two orthogonal linearly polarized radiation patterns in quadrature. The coupler outputs are connected to the antenna by two conducting pins that connect directly to the groundplane of the lower patch. The coupler uses the hi-band patch as a groundplane and is transparent to the radiation from the antenna. An antenna input connector is connected to the coupler input by means of a coaxial line through the center of the antenna. The isolation port is terminated in a surface mounted 50-ohm resister to ground through a quarter wave length open transmission line.

Abstract: An antenna for a land-based, mobile radio communication system, having a reduced size and shape, includes three, flat antenna dielectric panels, each covering one hundred, twenty degrees of azimuth. On each dielectric panel is formed two, interleaved microstrip antenna arrays having narrow vertical beam width. One of the antenna arrays receives signals and the other antenna array transmits signals. The receive array is circularly polarized. The panels are mounted in a triangular configuration about a central mast and a cylindrically shaped radome encloses the dielectric panels.

Abstract: A polarization twister for twisting the polarization of a wide angle incident electromagnetic wave is described. Specifically, the polarization twister includes a reflector for reflecting the wide angle incident electromagnetic wave, a dielectric substrate having a longitudinal axis, a spacer bonded on a first side thereof to the dielectric substrate and on a second side thereof to the reflector, and an array of meanderline conductive strips etched on the dielectric substrate. Each meanderline conductive strip has an axis extending at a 45.degree. angle with respect to the longitudinal axis of the dielectric substrate. In operation, the meanderline conductive strips serve to advance the phase of a parallel component of an incident E-field vector, and delay the phase of the perpendicular component thereof. Accordingly, the reflected field has its polarization twisted 90.degree. from the incident polarization.

Abstract: A dipole phase shifter for use in a phased array antenna includes an insulating substrate having first and second sides. A dipole element having first and second conductive dipole arms is formed on the first side of the insulating substrate and a PIN/NIP diode pair is mounted on the second side of the insulating substrate and electrically-connected to the first and second dipole arms, respectively. A coaxial RF transmission line having a center conductor extending through the insulating substrate connects an input signal to the phase shifter. Quarter-wave transformers are connected between the center conductor and the diodes to compensate for the forward and reverse bias reactances thereof. The first and second dipole arms serve as groundplanes for the quarter-wave transformers. The center conductor also serves as a common bias line which allows forward biasing of one diode and, simultaneously, reverse biasing of the other diode.