Miniature dual mode microstrip filters

Highly Selective Dual-Mode Microstrip Bandpass Filters Using Triangular Patch Resonators

“…The basic geometries used for the realization of dual-mode filters are loop [4][5][6][7] and patch resonators. Patch resonators employing circular, square and triangular shapes are reported [1], [8][9]. Patch resonators have many interesting features such as high power handling capability, lower conducting losses and ease of fabrication at millimeter waves.…”

“…Highly selective bandpass filters were realized by using two different resonant modes of triangular patch with cascading topology [8]. Dual-mode operation of equilateral triangular patch resonator was theoretically studied in [10], and they proved that dual degenerate mode is obtained by rotation and superposition of fundamental mode.…”

Design approach for bandpass filter using triple-mode stripline resonator

“…One corner of the center conductor is cut out, as shown in Fig. 2, due to the coupling between TM 10 and TM 01 [7]. The size of center conductor is 40 Â 40 mm, the length of feed lines is 5 mm, the diameter of the via holes is 0.8 mm, and the distance between them is 4 mm.…”

Compact Dual-Mode DGS Resonators and Filters

“…Dual-mode resonators attract much attention recently because they can reduce the number of resonators required for a same degree filter by half. Dual-mode resonators with two degenerate modes are usually in the forms of a square patch [1], a circular disk [2] or a circular ring [3]. However, they have disadvantages in the resonator size.…”

“…However, they have disadvantages in the resonator size. For example, S patch ≈ (λ g /2) 2 , S disk ≈ (1.84λ g /π) 2 , S ring ≈ (λ g /π) 2 , where λ g is the guided wavelength of central frequency [4]. A lot of structures have been investigated to reduce the size of the dual-mode resonators, such as cross-slotted patch [5], square ring [4], meandering ring [6], multiarc ring [7], capacitive loaded ring [8,9] and stub-loaded ring [10].…”