Electrical engineering

Physics

Band-pass filter

Low-pass filter

Stub (electronics)

Diplexer

Resonator

Filter (signal processing)

Waveguide filter

Engineering

Coupling (piping)

Multi-band device

Prototype filter

Antenna (radio)

Acoustics

Metallurgy

Materials science

Electronic engineering

Passband

Coupling coefficient of resonators

Optoelectronics

Coaxial

IEEE Transactions on Microwave Theory and Techniques

This article presents a simple design of a coaxial dual-band cavity filter and diplexer using stub-loaded resonators (SLRs). Based on the resonance characteristics of a coaxial SLR, the first two resonant frequencies can be tuned over a wide range by adjusting their structural parameters. Controllable external quality factors can be acquired by using the modified tapping structure for the two designated passbands. A coupling window and a coupling pin are proposed to obtain the expected coupling coefficients in the two bands. To demonstrate this concept, a third-order dual-band bandpass filter and an eight-pole diplexer are designed and fabricated. The measured results agree well with the full-wave simulation results.

Dual-Band Coaxial Filter and Diplexer Using Stub-Loaded Resonators