Abstract: A cellular radiotelephone communication system cell site equipment is provided. The cell site equipment includes a radio frequency transmitter operating as one signal frequency source. In addition, the cell site equipment includes a first and a second signal combiner device tuned to a first and a second signal frequency, respectively. Further, the cell site equipment includes a radio frequency switching mechanism, operatively coupled to the radio frequency transmitter, the first signal combiner device, and the second signal combiner device, for coupling the radio frequency transmitter to either of the first and the second signal combiner devices. In one embodiment, each signal combiner device includes a resonant cavity for isolating a signal frequency source from other signal frequency sources and a coupling for coupling the isolated signal frequency source to a common transmitter output.

Abstract: Transmitter combining apparatus includes up to five RF filters (100) coupled to a microstrip combiner (300) for combining up to five input signals for application to a common antenna. The RF filter (100) includes a ceramic resonator (116) sandwiched between first and second compensating discs (114 and 120) and first and second shield plates (142 and 148) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). Good thermal contact between the ceramic resonator (116), discs (114 and 120) and shield plates (142 and 148) is produced by a compressive force exerted by springs (144-147) of shield plate (142) when the top cover (112) is attached to the aluminum housing (124). The resonant frequency of the RF filter is tuned by means of an aluminum tuning shaft (102) and ceramic tuning core (118) which are positioned by brass bushing (133) in top cover (112).

Abstract: Transmitter combining apparatus includes up to five RF filters (100) coupled to a microstrip combiner (300) for combining up to five input signals for application to a common antenna. The RF filter (100) includes a ceramic resonator (116) sandwiched between first and second compensating discs (114 and 120) and first and second shield plates (142 and 148) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). Good thermal contact between the ceramic resonator (116), discs (114 and 120) and shield plates (142 and 148) is produced by a compressive force exerted by springs (144-147) of shield plate (142) when the top cover (112) is attached to the aluminum housing (124). The resonant frequency of the RF filter is tuned by means of an aluminum tuning shaft (102) and ceramic tuning core (118) which are positioned by brass bushing (133) in top cover (112).

Abstract: A helical resonator filter with increased bandwidth is provided for use as a wideband bandpass filter. The device is composed of a series of helical resonators cells cascaded with non-uniform cell spacing, thus providing an increase in coupling coefficients between cells. The increased bandwidth is thereby obtained without placing a burden on the exterior housing dimensions relative to a normally spaced narrow bandwidth filter and without substantially reducing the unloaded Q's or increasing insertion losses.