Bandstop Filter Synthesis Scheme for Reactively Loaded Microstrip Line Based 1-D Periodic Structures

Abstract

A 1-D finite electromagnetic bandgap (EBG) periodic structure is studied. In the structure, EBG behaviour arises from a unit cell comprised of a metallic patch sandwiched between microstrip line and ground plane. Reactive loading offered by patch size determines the bandgap position. A detailed parametric study of various physical structure parameters is presented as a basis to develop a interrelation between physical parameters of the structure and cutoff frequencies. Closed-form synthesis equations are then formulated using curve fitting techniques. Subsequently, a step-by-step design methodology is presented to get a close first pass approximation of structure dimensions for a given specification. This design method reduces the effort required for a designer to perform extensive electromagnetic simulations at early stages of the design. The proposed synthesis method is tested for a variety of commercially available substrates and different frequency ranges for validation. Comparison with electromagnetic (EM) simulations and measurement show that the proposed synthesis method provides first pass approximation of the physical structure dimensions with 94% accuracy. INDEX TERMS Bandstop filter, electromagnetic bandgap, filter design, microstrip line, periodic structure.

Metamaterial inspired electromagnetic bandgap filter for ultra-wide stopband screening devices of electromagnetic interference

“…The five unit-cell EBG structure has a significantly superior bandgap rejection any EBG reported to date. Although the proposed EBG structures have a highly sharp 3-dB roll-off, this is not as good as 35 . The shortcomings of 35 are its poor return-loss response and limited bandgap range.…”

“…Although the proposed EBG structures have a highly sharp 3-dB roll-off, this is not as good as 35 . The shortcomings of 35 are its poor return-loss response and limited bandgap range. The bandgap of the proposed EBG structures is substantially wider than any work reported to date.…”

Novel Selective Feeding Scheme Integrated With SPDT Switches for a Reconfigurable Bandpass-to-Bandstop Filter

“…From ring resonator theory, it can be said that the ring resonates when its input admittance is zero [40]. Thus, the resonant conditions are displayed as, (1) (2) Superscripts 1 and 2 represent the upper and lower arm input admittance respectively as defined in Fig. 2.…”

“…With the recent rise in the demand for electromagnetic spectrum due to the increasing spread of microwave and wireless system applications, reconfigurable microwave filters are anticipated to facilitate the growth of modern multi-functional transceivers operating in an immensely vigorous interference environment, without the need for complex and large in size filter banks. In this environment bandstop filters (BSF) [1][2][3][4][5][6][7][8][9] are the key components for elimination of high power-agile interferers close to the desired signal, whereas bandpass filters (BPF) are chosen for the selection of the desired RF signals [10][11][12][13]. Therefore recently, reconfigurable filters have become an essential component in wireless systems and have attracted a lot of attention.…”

A Compact Reconfigurable 1-D Periodic Structure in GaAs MMIC With Stopband Switching, Dual-Band Operation and Tuning Capabilities

“…The effect of important structure parameters on its performance and detailed synthesis scheme to design a filter circuit using this kind of periodic structure on PCB can be found in [33], which takes the system specifications as input and yields 1-D periodic structure geometrical dimensions as output. Detailed discussions on the effect of each structure parameter on its performance can be found in [20], [33]. However, the effect of spiral inductor parameters on the circuit performance is discussed here.…”