MULTIPLEXERS USING WEAKLY-COUPLED NETWORKS IN RF FRONT END CIRCUITRY

摘要

Multiplexing circuitry is disclosed that includes filtering circuitry, which provides a first transfer function between a common port and a first port and a second transfer function between the common port and a second port. The first transfer function and second transfer function provide a first passband and a second passband, respectively. The first transfer function also has a stopband provided within the second passband of the second transfer function due to the filtering circuitry including a first parallel resonant circuit provided in series in a first filter path being weakly coupled to a second parallel resonant provided in shunt with respect to a second filter path. The weak coupling between the first parallel resonant circuit and the second parallel resonant circuit thus naturally provides a stopband in the first transfer function within the second passband of the second transfer function.

主权项

1. Multiplexing circuitry comprising:
a common port, a first port, and a second port; filtering circuitry coupled to the common port, the first port, and the second port and configured to provide a first transfer function between the common port and the first port and a second transfer function between the common port and the second port wherein:
the first transfer function has a first passband and a first stopband;the second transfer function has a second passband wherein the first stopband of the first transfer function is within the second passband;a first parallel resonant circuit is provided in series in a first filter path connected between the common port and the first port; anda second parallel resonant circuit is provided in shunt with respect to a second filter path that is connected to the second port, wherein the second parallel resonant circuit is weakly coupled to the first parallel resonant circuit such that the first stopband is within the second passband.