New Negative Coupling Structure for Substrate-Integrated Cavity Resonators and Its Application to Design of an Elliptic Response Filter

Abstract

Abstract-This paper presents a new type of a negative coupling structure for designing elliptic-response filters with cross-coupling. The proposed coupling structure consists of short-circuited coupled transmission lines. Using the fact that insertion phase of the coupled line structure is different from that of an inductive iris, it is shown that the proposed coupling structure can be used as the negative coupling structure. In order to verify the proposed coupling structure, we designed a 4th-order cross-coupled elliptic-response bandpass filter with substrate integrated waveguide resonators. A pair of transmission zeros in measurement and simulation results validates that the proposed structure can be used as the negative coupling structure.

Novel Negative Coupling Structure for Rectangular Waveguide Cavity Filters

“…In waveguide cavity filters, the negative couplings are implemented by, for example, a slot at the maximum of the electric field [4], [5], twisted currents flowing through vias in substrate integrated waveguide (SIW) cavities [2], [6], [7], a virtual coupling in folded [8], [9], and cylindrical TM 011 -mode resonators [10], which are not always possible to fabricate, or utilizing higher-order resonances [11], [12], which result in spurious responses. In [13], [14], the negative coupling structures are implemented using current probes. However, their implementation requires additional low-Q structures, resulting in increased losses.…”

Realisation of controllable transmission zeros by perturbation technique for designing dual‐mode filter using substrate integrated hexagonal cavity

“…The implementation of diplexer using both dual-mode circular and elliptical cavity in SIW environment was demonstrated [13]. Lee et al [14] have emphasised on realising a new type of negative coupling structure which has been used to realise a fourth order cross coupled elliptic bandpass filter using fundamental mode of circular cavity. This negative coupling improves the selectivity by introducing two transmission zeros at both side of the passband.…”

Miniaturized Multilayer Dual-Mode Substrate Integrated Waveguide Filter With Multiple Transmission Zeros

“…Bandpass filters with high integration and sharp skirts are essential in the development of modern wireless and mobile communication systems [1][2][3][4][5][6]. Microwave dual-mode filters with microstrip or metal waveguide structure can provide valid solutions to satisfy these requirements owing to their high performance and easy design [7] Although the microstrip dual-mode filters are have been widely used and implemented, they have lower power-handing capability and lower resonator Q factor in higher frequencies [8,9].…”