High Q-Factor Bandstop Filter Based on CPW Resonator Broadside-Coupled to CPW Through-Line

Abstract

High Q-factor bandstop filter based on broadside-coupling between U-shaped coplanar waveguide (CPW) resonator and CPW through-line (CPWTL) is proposed in the present paper. The CPWTL is printed on the top layer of the dielectric substrate whereas the CPW resonator (CPWR) is printed on the bottom layer. Only over very narrow frequency band around the resonant frequency of the CPWR the microwave power flowing in the CPWTL is coupled to (absorbed by) the CPWR leading to a bandstop filter of very high Q-factor. A CPWR with side ground strips of finite width is shown to have much higher Q-factor than that of infinitely extending side ground planes. Owing to the lower profile of the CPW with finite-width, the radiation loss is reduced, and the structure has narrower frequency band for coupling, which results in much higher Q-factor than other published works. The dimensions of the CPWTL are optimized for impedance matching whereas the dimensions of the Ushaped CPWR are optimized to obtain the highest possible Q-factor. The effect of the loss tangent of the dielectric substrate material on the Q-factor is investigated. A prototype of the proposed filter is fabricated and experimentally studied for more understanding of the underlying physical principles of operation and for experimental investigation of the filter performance. The experimental measurements show good agreement with the corresponding simulation results.

Flexible Antenna with Circular/Linear Polarization for Wideband Biomedical Wireless Communication

“…The CPW has a length of L , the width of its central strip is W , and the width of each side slot is S . The characteristic impedance of the CPW is obtained based on W and S that are calculated using the CPW design equations [ 44 , 45 ]. The length of the CPW central strip extension to connect the antenna to the feed line is L .…”

“…The results of this investigation are presented in Table 2 . Furthermore, it should be noted that the dimensions of the CPW region are adjusted to improve the impedance matching where the analytic rules in [ 44 , 45 ] have been used as initial values and then optimized by EM simulation.…”

Flexible Irregular-hexagonal CPW-fed Monopole Antenna with Windmill-shaped Fractals for Ultra-wideband Technology

“…The antenna is stimulated through a co-planar waveguide (CPW) feed line, with the CPW's length designated as L g . The width of the central strip within the CPW is identified as W f , while the width of each side slot is represented as S. The CPW's characteristic impedance is determined by computing values for W f and S, employing the CPW design equations [19,20]. For connecting the antenna to the feed line, the CPW's central strip is extended by a length of L f .…”

Design of a Miniaturized Split-ring Resonator Based UWB Notched Bandpass Filter

“…The method of implementing a combination of slot etched semi-ellipse structure in the ground plane and U-shaped resonators short-circuited with a microstrip line for securing basic UWB filter characteristics and applying quarter wavelength open-circuited stubs loaded to the microstrip line for notch formation can also be noted [8]. Besides, a CPW through line on the top plane possessing broadside coupling with a U-shaped open-ended half wavelength CPW resonator in the ground plane is introduced where a high Q factor is produced by the microwave power flow in the coplanar waveguide through line (CPWTL) which occurs over a narrow region [9]. Next exploiting MMR as an elementary UWB filter designing mechanism and inclusion of various stubs, stepped impedance resonator (SIR), and different novel structures in it is the way to introduce notches at desired frequencies.…”