ARMY ELECTRONICS TECHNOLOGY AND DEVICES LAB FORT MONMOUTH N J
Recent demands for a very high resolution radar in terminal homing for missiles and shells and for radar surveillance in general, have generated a need for developing new concepts in low cost millimeter wave antennas. A means of providing electronic line scanning rather than mechanical scanning is desirable in order to reduce system complexity and high cost. It is especially important to eliminate the use of gimbals to mechanically scan an antenna, since they are expensive and slow. This paper describes the design and experimental findings of a novel approach for a side-looking electronic line scanner consisting of a dielectric silicon rectangular rod with periodic perturbations on one side. Angular scan is achieved by varying the frequency while the actual numerical values of the scan angles are a function of operating frequency, waveguide size height and width and perturbation spacing. An alternative approach was explored where the frequency was held fixed and the effective guide wavelength was varied electronically by modulating the conductivity of a PIN diode mounted on the dielectric waveguide. Antennas were designed for the n-1 spacial harmonic at operating frequencies in the 55 to 100 GHZ range.