Design of Planar Dual and Triple Narrow-Band Bandstop Filters With Independently Controlled Stopbands and Improved Spurious Response

Abstract

Abstract-A novel design of planar dual and triple narrow-band bandstop filter is presented by adopting the proposed meandered slot defected microstrip structure (MS-DMS) and the simplified spiral microstrip resonator (SSMR). Through this design, the stopbands of the dual-and triple-band bandstop filters can be individually controlled and the improved spurious responses are achieved. First, the fundamental and the first spurious resonances of the MS-DMS and SSMR are analyzed to provide the design rules. Then, by utilizing the prominent stopband of the MS-DMS and the stopband produced by the SSMR coupled to main microstrip line, a dual narrowband bandstop filter is constructed before its design procedure is outlined. Based on above investigations, a triple narrow-band bandstop filter is implemented by inserting extra SSMRs to another side of the main microstrip line of the dual-band filter to generate a new stopband. To verify the aforementioned design concepts, a dual and triple narrow-band bandstop filter are designed, simulated and tested. Both the simulation and measurement indicate that the fabricated filters exhibit good stopband/passband performance and improved first spurious resonance. Moreover, these filters are simple to design and quite compatible with planar fabrication technique, making them very attractive for practical applications.

Compact Triple-Band Bandstop Filters Using Embedded Capacitors

“…Our all three filters are compact against the reported filters, and the control on stopband is relatively easy. The loaded quality factors of our proposed filters are higher than the reported filter in [5][6][7][8][9][10][11][12][13][14]. The fabricated prototype is presented in Fig.…”

“…Multi-band bandstop filters play an important role and are tremendously preferred, which can be simultaneously used for stopping different signal frequencies. Some effective methods have been proposed to develop dual-band [1][2][3][4] and triple-band bandstop filters [5][6][7][8][9][10][11][12]. However, the design of triple-band bandstop filters (TB-BSFs) and controlling the stopband frequencies within the specified band are difficult.…”

“…Hence, relatively less works have been done on TB-BSFs [5][6][7][8][9][10][11][12]. Recently, some TB-BSFs are designed by using series LC resonators and admittance inverters [5], T-shaped defected microstrip structure [6], cross coupling stubs [7], square patch resonator [8], defected microstrip structure (DMS) and E-shaped defected ground structure (DGS) with open-loop resonators coupled to the microstrip line [9], U-shaped DGS [10], Hilbert-Fork resonator [11] and by using meander line stepped impedance resonator [12]. Multi-ring complementary split ring resonators (multi-ring CSRRs) [13], and meandered DMS (MDMS) structure [14] have also been utilized to design the Triple-Band BSFs.…”

Parametric studies on effects of defected ground structure (DGS) for dual band bandstop microstrip filter

“…The size of configuration is reduced by using method of dual band filter [3][4]. In the recent past, the researchers have been utilized several kinds of design and method of dual band bandstop filter [5][6][7].…”

A Compact Tunable Dual-Stop-Band Filter Based on DMS and DGS

“…To filter out several interfering signals in these systems, independently tunable dual-stop-band filter is being increasingly adopted in the industries. Conventionally, most of works are about ordinary bandstop filters [2,3], little of which involve with tunable dual-stop-band filters [4]. In [5][6][7][8][9], tunable one stop-band filters are proposed based on varactor loaded split ring resonators, RF-MEMS metamaterials and DGS respectively.…”