Vinay Ravindra

A Dual-Polarization

This paper investigated the possibility of using an

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-Band Traveling-Wave Antenna Panel for Small-Satellite Synthetic Aperture Radar

-band traveling-wave antenna for application in synthetic aperture radar (SAR) on a small-satellite platform. A rectangular slotted parallel-plate antenna panel capable of radiating dual polarization over the same physical aperture was selected for this purpose. The design procedure, which provides for an optimal antenna pattern in a SAR application, is described. A meta-heuristic multiobjective optimization algorithm was applied to synthesize an appropriate far-field pattern, which enhances the quality of the SAR image. Subsequently, the optimization results were used to build a more realistic model of the antenna panel in electromagnetic simulation software. An antenna panel was fabricated, and its electrical characteristics were measured. The fabricated prototype weighed 1310 g and measurements showed nearly 50% aperture efficiency for both circular polarizations [34.6-dBic right-hand circular polarized (RHCP), 34.5-dBic left-hand circular polarized (LHCP), and peak gain at 9.65 GHz], with low side-lobes. A beam shift of 2.1° was observed between the RHCP and LHCP beams at the design center frequency and was later analyzed to be the result of an error in the modeling of the adhesive layer.

Cylindrical cavity microwave power combiner with microstrip line inputs and rectangular waveguide output

A compact microwave power combiner for combining output from six solid-state power amplifiers is studied. The combiner consists of 6 standard microstrip line inputs from high power amplifier, resonant cylindrical cavity and one standard rectangular waveguide output. The effect of input power amplifier failure is also studied and simulation results are described. Insertion loss of less than 0.3 dB over 200 MHz bandwidth in X-Band is simulated.