Waveguide ASK Modulator Using Switchable FSS

• Published in: Journal of infrared, millimeter and terahertz waves Vol. 41; no. 12; pp. 1478 - 1487
• Main Authors: Kiani, Ghaffer Iqbal, Hussaini, Mohammed Abdullah
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2020; Springer Nature B.V
• Subjects: Apertures; Classical Electrodynamics; Diodes; Direct current; Electrical Engineering; Electronics and Microelectronics; Engineering; Frequency response; Frequency selective surfaces; Incident waves; Inductance; Instrumentation; Keying; PIN diodes; Superhigh frequencies; Unit cell; Waveguides; Radio frequency; Modulator; Amplitude shift keying; Frequency selective surface; Switchable; PIN diode; Waveguide
• ISSN: 1866-6892; 1866-6906
• DOI: 10.1007/s10762-020-00703-4

A waveguide modulator using switchable frequency selective surface (FSS) for amplitude shift keying modulation (ASK) at super high frequency (SHF) has been presented. The FSS consists of rectangular loop aperture elements with two PIN diodes at 180 ∘ intervals on every unit cell across the aperture. A minimum transmission isolation of 30 dB has been achieved at resonance frequency when the diodes are switched between ON and OFF states. The PIN diode parameters are modeled using Keysight’s Advanced Design System (ADS) software to find the missing value of inductance and match the results presented in its datasheet. The proposed FSS modulator can operate either for transverse electric (TE) or transverse magnetic (TM) polarizations subject to the positioning of the incident wave due to its rectangular geometry. Positive direct current (DC) biasing is introduced from the front while negative DC biasing has been connected on the back-side of the unit cell FSS. Both the diodes are employed orthogonal to the principal axis of the FSS to reduce the impact of negative bias-line on overall frequency response. Both simulation and measured results have been presented.