Reconfigurable Coplanar Waveguide (CPW) and Half-Mode Substrate Integrated Waveguide (HMSIW) Band-Stop Filters Using a Varactor-Loaded Metamaterial-Inspired Open Resonator

Abstract

An open ring resonator (ORR) loaded with a varactor diode is designed and implemented in order to achieve high-performance tunable band-stop filters in planar technology with a compact size. This varactor-loaded ORR (VLORR) is versatile. It allows a shunt connection with different planar waveguide sections. In this paper, it has been connected to a coplanar waveguide (CPW) and a half-mode substrate integrated waveguide (HMSIW). As a reverse bias voltage is applied to the VLORR, a continuous tuning over the resulting stop-band can be achieved. To illustrate the possibilities of the VLORR, three prototypes have been designed, fabricated, and characterized. The three prototypes show an outstanding performance, with a rejection level at the resonant frequency and a tuning range greater than 12 dB and 85%, respectively. This VLORR has high potential value in microwave communication systems to eliminate unwanted signals.

Frequency-Tunable SIW Band-Reject Filter with Increased Fundamental Mode Bandwidth for Spectrum Underlay Cognitive Radio

“…The VD capacitances are taken from its datasheet [18]. The series RLC circuit is used in the simulations Dual-band-stop filter with one tunable stopband 2 3.5-4.1 GHz (15%) [8] Frequency and bandwidth tunable band-stop filter 2 2.8-3.4 GHz (19.3%) [9] X-band tunable band-stop filter 2 10.02-10.34 GHz (3.1%) [10] Half-mode band-stop filter 1 2-2.5 GHz (22.2%) [11] Coaxial band-stop filter 2 0.77-1.25 GHz (47%) [12] Octave tunable combline band-stop filter 2. The capacitance of the varactor diode depends on its reverse bias voltage, as shown in Equation (1), where C Vr is the capacitance of varactor diode, Cp is the parasitic capacitance, C J0 is the PN junction capacitance at zero bias, M is the constant, Vj is the junction potential, and Vr is the reverse bias voltage.…”

“…Moreover, achieving the tunable frequency property involves the lumped elements that make microstrip filters more vulnerable to losses compared to SIW filters. There are many SIW band-stop filter-based papers available in the literature [7][8][9][10][11][12]. For underlay CR, the frequency-tunable bandwidth should be as high as possible so that the secondary users can access wider frequency bandwidths.…”

Compact Wideband Groove Gap Waveguide Bandpass Filters Manufactured with 3D Printing and CNC Milling Techniques

“…Microwave filters are key devices in the communications payload of satellites [1]. Among different technologies, a rectangular waveguide (RW) is often employed to implement them at microwave/mm-wave frequencies, due to its low loss, high quality factor, and high-power handling capability with regards to planar and substrate integrated waveguide (SIW) solutions [2][3][4][5][6][7]. However, unlike RW technology, planar and SIW filters have a low profile and weight, small sizes, and allow the easy integration of active components.…”

E-Textile Metamaterials: Stop Band Pass Filter

“…On the other hand, metamaterials (MTMs) [3,4] are an attractive topic for researchers recently, which they have applied for improving microwave systems such as antennas, filters, and sensors [5][6][7]. Recently, MTMs have been integrated into textiles and have led to the development of MTM in a variety of reported fields, such as e-textile metamaterial transmission lines [8], MTM textile sensors [9], MTM microwave absorbers [10], double ring resonators garment antenna [11], and (in the field of filtering) e-textile band pass filters [12].…”