Multilayer Microstrip Bandpass Filter Design Using Galvanic Coupling

In this paper miniaturization of a microstrip bandpass filter using multilayer structure based on galvanic coupling between parts of half-wavelength resonator is discussed. Sample structure is realized for the frequency characteristics of a GPS receiver as an example, with a lower bandwidth limit in the L5 frequency band and an upper limit in the L2 frequency band, with a central frequency of 1.209 GHz. Proposed method can reduce the size by at least two times for MPL and more for multilayer technology.