HTS AMPS-A and AMPS-B filters for cellular receive base stations

The multiple, interleaved pass band nature of the AMPS cellular system provides an excellent opportunity for high performance HTS filter technology for base station reverse link applications. The 25 MHz spectrum is divided into 4 unequal bands, 2 each for the A and B operators. For AMPS-A, the two band pass filters are connected in parallel, while for AMPS-B a band pass filter is cascaded with a band reject filter. All band pass filters have finite transmission zeros and the band reject filter is designed to have an equal ripple stop band. The design and performance of high selectivity filters for this application is described.