A 2-Bit Quad Band Frequency Selective Surface Furnishing Multifunction Behaviour at Two Bands

A multifunction FSS contributing 4 resonant pole frequencies is presented in this manuscript. Two bands possess multifunction filtering and two have fixed behaviour. The parallel biasing technique is utilized in this design and only two p-i-n diodes are integrated into the quad band designed unit cell. Two p-i-n diodes controlled by biasing sequence outcome four different sorts of spatial filtering responses. The 4 transmission pole resonances are organized at 1.9 GHz, 3.33 GHz, 3.78 GHz and 5.0 GHz frequencies. First spatial filtering combination is achieved with biasing arrangement of 00 code i.e., no bias at all p-i-n diodes. This code outcomes three bands at 1.9 GHz, 3.78 GHz and 5.0 GHz frequencies and shields the 3.33 GHz band. Forward biasing to both the diodes outcomes in two transmission pole resonances occurring at 3.33 GHz and 5.0 GHz while shielding to 1. 9 GHz band. The multifunction design structure is symmetric to all polarizations of wave for 11 and 00 combinations. The other biasing combinational arrangements 10 and 01 are responsible for polarization conversion among TM and TE modes at the same bands supplied by 11 and 00 combinations. The angle stability for the multifunctional transmission resonances 1.9 GHz, 3.33 GHz and 3.78 GHz is executed upto 45o. The fourth transmission pole resonance is not angularly stable which can be exercised for systems which work at normal angles such as for one way communication e.g., at transmitter ends. The design of quad band multifunction structure is flexible to electromagnetic behaviour change amid transmission/reflection, frequency switching and polarization conversion amid TE/TM at the two bands which add low insertion loss to the transmitting signal from the structure.