Filtering apparatus

摘要

A filtering apparatus includes a passband of a first-level unit which is formed by at least three coaxial filters covers a passband of a second-level unit which is formed by at least three dielectric filters, and a bandwidth of the first-level unit is twice the bandwidth of the second-level unit, so that when the coaxial filters are coupled to the dielectric filters, insertion loss of the coaxial filters is reduced, thereby reducing overall insertion loss of the filtering apparatus. By making a transmission zero of the first-level unit be located at a second harmonic frequency point of the second-level unit, the filtering apparatus can have high suppression on a second harmonic, thereby obtaining relatively desirable far-end suppression performance.

主权项

1. A filtering apparatus, comprising:
a first-level unit; and a second-level unit, wherein the first-level unit is formed by at least three coaxial filters, the at least three coaxial filters are arranged in sequence, each coaxial filter is coupled to an adjacent one of the at least three coaxial filters in a first arrangement direction, and two nonadjacent coaxial filters in the first arrangement direction in the at least three coaxial filters are inductively coupled to generate a transmission zero at a high frequency end of a passband of the first-level unit, wherein the second-level unit is formed by at least three dielectric filters, the at least three dielectric filters are arranged in sequence, and each dielectric filter is coupled to an adjacent one of the at least three dielectric filters in a second arrangement direction, wherein a last coaxial filter of the at least three coaxial filters in the first-level unit is coupled to a first dielectric filter of the at least three dielectric filters in the second-level unit, wherein the passband of the first-level unit covers a passband of the second-level unit, and a bandwidth of the first-level unit is twice the bandwidth of the second-level unit, and wherein the transmission zero of the first-level unit is located at a second harmonic frequency point of the second-level unit.