Synthesis of a Wideband Diplexer Based on Interdigital Resonators for the Antennas Of Mobile-Communication Base Stations

We study theoretically and experimentally a new design of the diplexer for mobile-communication base stations, which is based on interdigital resonators. A high-performance diplexer for operation in the frequency ranges 690–862 MHz and 880–960 MHz has been developed and manufactured. The diplexer is synthesized on the basis of an efficient combined method including the use of the coupling matrix technique, solution of eigenvalue problems for single and coupled rod-type resonators, and electrodynamic simulation of filters and the diplexer. The proposed design has a high potential for realization of diplexers with wide, moderate, and narrow passbands in the mobile-communication frequency ranges.