B. K. Sarkar

Quasi-Optical Power Combining Techniques

This paper brings about the past and recent trends in the design of solid-state transmitter in the millimeter and submillimeter-wave frequencies using quasi-optical techniques where many devices are efficiently combined to give moderately high power useful for radar applications. In quasi-optics, the cavity dimension can be of many wavelengths, thereby allowing large number of solid-state devices to be integrated without any moding problem usually present in waveguide combiner circuits. Combining efficiency is quite high since combination takes place in the space. Some work carried out at SAMEER is also reported.

Enclosed cylindrical thick microstrip lines and their use in a high-power 1: N power divider/combiner

Closed-form equations for the characteristic impedances of even and odd modes are given for an enclosed cylindrical microstrip line with finite thickness (CMSWFT) with the use of the conformal mapping technique and the available equations for microstrip lines. The enclosed structure is also suitable from the EMI and EMC points of view. A compact 1:5-way, equal in phase, power divider/combiner has been realized with the use of this structure at 350 MHz. This power divider/combiner is suitable for high-power applications in VHF and UHF bands. The limitations regarding the maximum output ports are discussed. Good performance of the power divider confirms the theoretical procedure.