Compact band‐stop filters using π‐Shape DGS and π‐shape DMS

Abstract

Compact π‐shape defected ground structure (DGS) and π‐shape defected microstrip structure (DMS) are proposed. Their resonant characteristics are analyzed using HFSS 12. Two band‐stop filters based on π‐shape DGS and π‐shape DMS are presented. One filter is composed of π‐shape DMS. Another filter is composed of π‐shape DMS and π‐shape DGS. The resonant characteristics of the filters can be changed by changing the structure parameters, especially the length a. Using π‐shape DGS, the performance of the band‐stop filter is improved and the area of the filter remains the same. Both two proposed band‐stop filters have two transmission zeros at each edge of the stop‐band. Finally, two band‐stop filters are fabricated and measured. The simulated results are basically consistent with the measured ones. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2504–2507, 2014

Multiband Bandstop Filter using an I-Stub-Loaded Meandered Defected Microstrip Structure

“…A lowpass to bandstop frequency variable transformation [1], a coupling technique [3], stepped-impedance-resonator (SIR) [4], [5], defected ground structure (DGS) [6][7][8][9] and defected microstrip structure (DMS) [9][10][11][12][13], are some widely used techniques that are commonly employed for designing multiband BSFs. Size is the primary concern in using passive elements during lowpass to bandstop transformation, the existence of spurious resonance is prominent in filters employing SIR, whereas filters using DGS have a major constraint in terms of radiation from the ground plane.…”

Design of Single-Band to Hexa-Band Bandstop Filters

“…The spurious frequency also appears at 5.9 GHz with 8 dB attenuation level. The center frequency of the Single-Band to the Quad-Band Bandstop filters can be approximately obtained using expression (1). where ε 1 eff s , ε 2 eff s and ε 3 eff s are the effective dielectric constants for different folded U-slots in microstrip line as well as in the ground plane.…”

“…Again to design the TB-BSF, three folded U-slots in the microstrip line have been used. The sizes of the folded U-slots are obtained using Equation (1). Two outer slots are used to get the first resonance frequency at 2.0 GHz; however, the central slot is used to obtained the second resonance frequency at 4.76 GHz.…”

“…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 Single-Band [1] Dual-Band [2][3][4][5][6] and Triple-Band Bandstop filters [7][8][9][10][11][12][13][14]. However, the design of Triple-Band Bandstop filters (TB-BSFs) and controlling the stopband frequencies within the specified band are difficult.…”

A stepped-impedance bandstop filter with extended upper passbands and improved pass-band reflections

“…1,2 Recently, various performances of bandstop filters have been investigated, such as dual/mutli-band operations, 3,4 size reduction, 5 and upper-passband extension. 6 As an ideal bandstop fitler, it is always expected that the bandstop performance occurs only at the desired frequencies while the low insertion-loss passband locates at other pass frequency bands.…”