A procedure to design and optimize triaxial horn antennas is presented. Under Matlab control, a powerful body-of-revolution code is used to analyze the simultaneous performance of tri-band horns. A simultaneous S/X/Ka triaxial horn is designed as an example.
An 82 to 98 GHz medium power amplifier is presented in a commercially available 0.1 µm GaAs process. The amplifier achieves greater than 20 dB gain and a measured Psat above 20 dBm across the frequency range. The maximum Psat of 22 dBm is measured at 96 GHz, corresponding to a power density of 395 mW/mm. A peak PAE of 13.3% is measured at 96 GHz.
Multi-beam gradient-index (GRIN) lenses are investigated to enable high aperture efficiencies and 2-D wide angular coverages. Metasurface composed of engineered elements with varied refractive indices is employed to implement the lens. Innovative methodologies are developed to calculate refractive-index distributions on the lens as well as the corresponding feed positions for multiple beams. A three-metal-layer element is developed to enable the variation of effective refractive index. Microstrip patch array antennas are designed as feed sources. Thirteen feed arrays are arranged on two focal arcs in xoz and yoz planes. A GRIN lens prototype is constructed, radiating multiple beams in a wide range of ±45° in two orthogonal planes with low scanning losses. The peak realized gain is 21.8 dBi with an aperture efficiency of 62.8%. The operating bandwidth is 22.2% from 12 GHz to 15 GHz.
In this paper, an electromagnetically transparent dipole working at the low-band (LB, 1.7-2.5 GHz) is proposed to simultaneously suppress the cross-band scattering and coupling to the high-band (HB, 4.4-5.0 GHz) antenna in a dual-band array. Dual-functional patches with vias are loaded on radiating arms of the LB dipole, which can introduce reversed induced-currents at the HB to restore the deteriorated HB radiation patterns and improve cross-band isolations at the HB. After the loading, HB patterns are well recovered, showing great consistency with the patterns of the HB dipoles operating alone. The transmission coefficients between the LB and HB ports are also greatly reduced.
In this paper, modulated metasurface based multibeam antenna is presented. The impedance superposition method of all impedance modulations for different beams is utilized in the design. The current reported multi-beam modulated metasurface has a very small number of beams due to the mutual interference of different impedance modulations. It is found that the source locations for each beam play a key role in interference suppression. Instead of using the time consuming full-wave simulation-based optimization, in this paper, the optimal source locations are obtained by using the aperture fields calculated from the zeroth-order approximation of the currents on the metasurface. A five-beam modulated metasurface antenna has been designed, providing an angular coverage up to ±30°. The peak realized gain for the broadside beam is 21.3 dBi at 14.30 GHz.
