Compact Spatial Band-Pass Filters Using Frequency Selective Surfaces

Abstract

Abstract-In this paper, spatial-band pass filters consisting of frequency selective surfaces (FSSs) are designed in order to realize both the desired transfer function of the filter in the frequency domain and drastic size reduction. Each FSS is made of aperture elements and patch elements. In this design method, the shape of each FSS is designed by a genetic algorithm (GA) so that the resonant curve of each FSS fits to the resonant curve which can be obtained from an equivalent circuit approach. By locating these designed FSSs at the intervals of quarter wavelength a spatial band pass filter is realized. Furthermore, a technique which controls the frequency response of each FSS has been applied to reduce the longitudinal size of filter. By this technique the FSSs are located at the intervals which are much shorter than a quarter wavelength, keeping the desired transfer function. Through a designed example it is shown that the half longitudinal length of a typical spatial filter can be obtained without any additional structure. Magnetic type spectral domain dyadic Green's functions are derived, and the characteristics of a spatial band-pass filter are calculated by means of the coupled magnetic filed integral equation which accurately takes higher order mode interactions. Derived linear matrix equations are solved using method of moment (MoM). The effectiveness of the proposed structure and its performance are verified and validated by designing and simulating an equal ripple spatial band pass filter at X-band.

High Gain Compact Microstrip Patch Antenna for X-Band Applications

“…Aperture and patch screens generally give complementary frequency responses, the field is totally transmitted at the resonant frequency of the aperture while a screen comprised of patches will be nearly totally reflected at the resonant frequency of the patches [10]. Frequency selective surfaces (FSSs) have been investigated for a variety of applications such as bandpass and bandstop spatial filter [11][12][13][14], radar absorbers [15][16][17], and artificial electromagnetic bandgap materials [18]. It can also be used as Specific Absorption Rate (SAR) [19].…”

Dielectric backed conducting strips as inductive element in spatial band-pass filter design

“…In [8][9][10] band-pass filters based on cascading substrate integrated waveguide (SIW) cavities have been designed. In [11] a spatial band-pass filter using FSSs is presented in which each FSS pattern is designed using a genetic algorithm. The developed design method in [11] uses patterned planes as resonating FSSs to realize spatial band-pass filters.…”

“…In [11] a spatial band-pass filter using FSSs is presented in which each FSS pattern is designed using a genetic algorithm. The developed design method in [11] uses patterned planes as resonating FSSs to realize spatial band-pass filters. In addition, this method can be used to design a desired transfer function using patterned planes in the frequency band.…”

Multi-Layer Aperiodic Dielectric Stack Structures for High Performance Electromagnetic Spectral Shaping from mm-Wave to mid-IR Frequencies

“…The measured insertion loss (IL) ranged from 1.5 dB to 2.7 dB, and the response was stable for oblique angles of wave incidence up to 40 . The work done in [22] shows a BP FSS designed using GA optimized metallic structures to fit a required response. The BP response was centered at 10 GHz, with a 3-dB bandwidth of around 2 GHz, with minimal variation for oblique angles of incidence up to 15 shown in simulation.…”

“…The conventional methods of fabricating FSS is using printed circuit boards (PCB) [21,22,23,2,24,25,26] and IC technology [27]. These processes rely on several steps and masks.…”