Tray Based Millimeter-wave Quasi-Optical Amplifiers and Dual Polarized Phased Arrays

Abstract

At millimeter wavelength, spatial power combining techniques offer a viable approach to realize compact, reliable, lightweight, robust, higher-power and economical systems This work focus on the tray based perpendicularly fed array systems, several design issues such as bandwidth improvement, power combining efficiency, dual polarity and beam steering were addressed in this thesis.

A broadband tray based spatial power amplifier that employs dielectrically filled miniature horn arrays was investigated. Bandwidth improvement was achieved by replacing the patch arrays of an earlier design with the broadband dielectrically filled miniature horn arrays. This 5x5 spatial power amplifier with miniature horn arrays has a 3dB bandwidth of 1.32 GHz (13%), which is more than 4.5 times the 3 dB bandwidth of the perpendicularly fed patch array spatial power amplifier.

This work presents experimental and numerical investigations on a 49-element Ka-band amplifier array. This study is aimed at determining the origin of various losses in the amplifier array. Passive simulation data confirms that the load seen by the active devices is well matched and that most of the power is coupled to the LSE10 mode. This means that coherent power combining should take place if there is no phase and amplitude variation due to the active devices and phase correcting dielectric lenses.

This thesis presents a single aperture multibeam spatial power combining system that can support two separate polarizations. A Rotman lens is used as the power dividing network, which also has the ability to scan the beam over discrete angles. 1x9 dual polarized array was designed to demonstrate the beam steering in azimuth plane. The entire system is designed for the Ka band, with a center frequency of 32.6GHz. Through simulations and measurements, a ±30 degree scan range was achieved for the horizontal and vertical polarizations. The cross polarization for both the vertical and horizontal polarization ports was better than –16dB.