Design of Different Selectivity Dual-Mode Filters With E-Shaped Resonator

Abstract

Abstract-A novel bandpass filter design method of achieving different selectivity based on E-shaped dual-mode resonator is presented. The characteristic of the E-shaped dual-mode resonator is investigated. The technique of utilizing capacitive and inductive input-output cross-coupling to generate two adjustable transmission zeros at stopband is explored intensively. Advantages of this type of filter are not only its dual-mode resonator and miniaturization, but also its controllable transmission zeros. The coupling scheme is presented to model the operations of these filters. Four dual-mode microstrip BPFs have been designed, fabricated, and measured. Both the simulated and measured results are presented. The exemplary filters verify the feasibility of the new design method.

Design Filters Using Tunable E-Shaped Dual-Mode Resonators for Lower-Ultra-Wideband and Upper-Ultra-Wideband Applications

“…Actually, this structure may also be considered as a stub-loaded resonator [22][23][24]. In previous reports, traditional E-shaped resonator structures are basically used for the design of narrow band (fractional bandwidth less than 10%) filters and seldom be used in the design of wideband filters [25][26][27]. Figure 1(b) shows the improved tunable E-shaped dual-mode microstrip resonators.…”

Compact Dual-Mode DGS Resonators and Filters

“…The open-stub loaded resonator has a size of about λ g /8 by λ g /8 [11], and the short-stub loaded resonator may be designed to be much more compact [12]. Nevertheless, feed structures of the circuits using dual-mode resonators, such as bandpass filters with source-load coupling [13,14] and dual-band filters [15,16], cannot be designed flexibly. Therefore, dual-mode resonators with flexible feeding schemes are highly desired.…”

A Novel Dual Mode Substrate Integrated Waveguide Filter With Mixed Source-Load Coupling (Mslc)

“…Also, a high precision mechanical adjustment or a subtle tuning mechanism is needed to obtain satisfying filters [5][6][7]. Although the microstrip dual-mode filters are easily designed and integrated into the high density layouts, they have lower resonator Q factor and lower power-handing capability [8,9]. Recently the substrate integrated waveguide (SIW), which is synthesized in a planar substrate with arrays of metallic via, has provided a useful technology to design low-profile, low-cost, and easy integration waveguide filters [10,11].…”