Patent ID: 7738933
Filing Date: 2010-06-15
Classification: H03J,Y10S

Abstract:
1. A tuning circuit for a narrow band filter, comprising a resonator comprising a half-loop inductor and a first interdigital capacitor connected in parallel between a first end and second end separate from the first end; a first shunt capacitor having a first terminal coupled to the first end of the resonator and a second terminal coupled to a ground node; a second shunt capacitor having a first terminal coupled to the second end of the resonator and a second terminal coupled to the ground node, wherein a capacitance of the second shunt capacitor is less than a capacitance of the first shunt capacitor; and a second interdigital capacitor having a first terminal coupled to the second end of the resonator and a second terminal coupled to a voltage-sensitive device; wherein a capacitance of the second interdigital capacitor is adjusted by a voltage applied to the voltage-sensitive device therein setting a resonant frequency of the resonator, and wherein a voltage regulator regulates the voltage applied to the voltage-sensitive device.