High rejection multilayer C-band DBR planar filter

This paper reports on the design of multilayer bandpass filters dedicated to a spatial application. A dual behavior resonator (DBR) topology and a multilayer technology were chosen so as to enhance rejection level. In addition to bringing a large characteristic impedance range, this technology allows filter miniaturization thanks to the low inter-resonator coupling. Moreover, the use of a "filter in filter" approach permits the control of spurious resonances in the out-of-band and reduction of the filter whole size. Two examples of filters highlight the benefits of this procedure. Experimental results are presented and discussed. An alternative method to the global electromagnetic simulation is also proposed.