Novel dielectric waveguide filter using isosceles right‐angled triangular resonators

Abstract

A novel dielectric waveguide filter based on isosceles right‐angled triangular (RAT) resonators is presented in this letter. By connecting the vertices of four isosceles RAT waveguide cavities, a square fourth‐order cross‐coupled waveguide bandpass filter is formed. The presented filter uses the partition wall and shallow blind hole to realize positive coupling and the deep blind hole to realize negative coupling. Moreover, the filter facilitates debugging and testing by setting the debugging blind hole on one side of the waveguide and setting the feed blind hole on the opposite side. The design, analysis, and simulation of the physical model of the filter are discussed. The fabricated filter has a center frequency of 3.5 GHz, relative bandwidth of 5%, insertion loss of less than 1 dB, in‐band return loss of more than 15 dB, and two out‐of‐band transmission zeros at 3.27 and 3.65 GHz.

A novel cross‐coupled filter with triangular resonators

“…The SMA probe is welded to the sensor, since the electric field direction of the probe is the same as that of the I/O resonator, the main mode in the resonator is excited to achieve I/O coupling. The external Q value 12 of the I/O structure is obtained: $$${Q}_{e}=\frac{\pi {f}_{0}\tau }{2},$$$where τ is the group delay of S11 and f 0 is the center frequency.…”

Novel compact bandpass filter using sextuple‐mode ceramic cavity resonator

“…6 Moreover, dielectric resonators with surface metal coating can reduce filter sizes. [7][8][9][10][11] The structure decomposed method is effective for designing filters with complex configuration. 12 However, for multimode dielectric cavity filters, methods of frequency tuning, feeding, coupling, and spurious-free window expanding are still required to be improved.…”

“…The inherent harmonics of multimode filters very close to the passband are usually reduced by modifying original structures, 5,6 or by cascading simple wideband filters 6 . Moreover, dielectric resonators with surface metal coating can reduce filter sizes 7–11 . The structure decomposed method is effective for designing filters with complex configuration 12 .…”