Analysis of frequency-selective surfaces on a biased ferrite substrate

Abstract

across every diode. Furthermore, it is expected that the higher the values of the surface-mount resistors, the smaller the microwave ohmic losses in the passband FSS region will be.Having incorporated the surface-mount resistors, the experiment for the single diode-C FSS was repeated. The results are shown in Figure 4(a). Also shown in Figure 4, are the tuning range results of the 2 diode B in series FSS and 2 diode C in series FSS. The results demonstrate that the use of resistors improves the band-stop filter performance. Wideband tunability, well in excess of 500 MHz, can be seen in Figure 4(c). It must be stressed that the tunability of varactor-diode-based FSS is achieved with negligible power consumption.When using diodes of high tunability and high resistance, such as diode B, FSS configurations with diodes in parallel [ Fig. 2(f)] can be employed. These configurations improve the filter attenuation by reducing the total resistance at the expense of reduced tunability. This is confirmed by comparing Figures 3(b) and 4(d). CONCLUSIONIn this paper, it has been demonstrated that the presence of biasing electrodes distorts the frequency response of tunable FSS and that this distortion is avoided through the novel use of high value (1 M⍀) surface-mount resistors. Furthermore, significant wideband tuning can be achieved using varactor diodes in series configurations at the expense of an increase in the overall FSS element resistance (which lowers the Q factor and increases the bandwidth). This resistance was found to decrease when the diodes were used in parallel configurations.Improvements in printing technology, which we are currently researching, will enable the proposed configurations to be employed in low-cost large-scale FSS deposition on a variety of substrates, such as wallpaper. Furthermore, although the proposed structures were required to block only one polarisation, as they were employed in a waveguide setup, current research work demonstrates that dipoleelement and loop-element tunable FSS can be fabricated to block linearly polarised incident waves of arbitrary electric-field orientation; this will be the subject of a forthcoming paper. ACKNOWLEDGMENTThis work was funded by Ofcom under the Spectrum Efficiency Scheme (contract no. AY4462), managed by Culham Electromagnetics and Lightning Ltd.

Scattering from a Frequency Selective Surface Supported by a Bianisotropic Substrate

“…Chang, Langley, and Parker report experimental results for FSSs printed on ferrite substrates [4]. The main idea is that a static magnetic field, applied on the ferrite substrate, changes the permeability of the substrate [2,[14][15][16]. Chiral substrates have been analyzed in Refs 7,10,11.…”

Novel Electrostatically Tunable Frequency Selective Surface with PZT/FeGaB Films

“…Because of good filtering properties, FSS is widely used in the various frequencies like microwave, millimeter wave, infrared, and even light waves, receiving great attention in both military and civilian [2]. To obtain a tunable property of the resonant frequency, FSSs with ferrite materials whose properties can be controlled through the use of a DC magnetic bias field are investigated a lot in recent years [3][4][5][6][7].…”

Resonant Characteristics of Frequency Selective Surfaces on Ferrite Substrates

“…The extra degree of freedom offered by the biased ferrite substrates can be used to obtain a number of novel characteristics. FSSs on ferrite substrates are well investigated for their tunable property [4][5][6]. In [5], a cross dipole FSS on a ferrite substrate is studied and a tuning range from 17.2 GHz to 19.2 GHz is obtained.…”

“…FSSs on ferrite substrates are well investigated for their tunable property [4][5][6]. In [5], a cross dipole FSS on a ferrite substrate is studied and a tuning range from 17.2 GHz to 19.2 GHz is obtained. In [6], the resonant characteristics of square loop FSSs on biased ferrite substrates are discussed based on the experiment results measured in a waveguide simulator.…”

“…Frequency selective surfaces are widely used as filters and absorbers in microwave, millimeter wave and far infrared community [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. They basically consist of periodic arrays of conducting patches or apertures on a conducting sheet.…”