Gain enhancement of antenna using tuned complementary FSS for wireless communication

This article explains a tri-band low-cost monopole tunable complementary frequency selective surface (C-FSS) fractal antenna of similar FSS and substrates area 21.13 mm x 24.81 mm, i.e. 0.4426${{\rm{\lambda }}_0}$lambda 0 x0.4962${{\rm{\lambda }}_0},$lambda 0, where ${{\rm{\lambda }}_0}$lambda 0 is free space wavelength. The offset feeding technique and a fractal shape are used to achieve dual polarisation (linear and circular). An FR-4 substrate with a thickness of 1.6 mm was used to fabricate the radiating patch and C-FSS separately. Distance between two substrates is adjusted to achieve enhanced gain without affecting the tri-band nature. For achieving tuning, four PIN diodes (BAP 65 02115) are attached in C-FSS. PIN diode switching and radiation characteristics have been measured and compared with the simulated results of the proposed C-FSS fractal antenna and found in the same shape and pattern with a minor deviation in resonating frequencies. Maximum peak gain (with C-FSS) achieved by the antenna at three resonating frequencies 6.0 GHz, 9.05 GHz and 11.56 GHz are 8.24dBi, 6.04dBi and 8.63dBi, respectively, as compared to without C-FSS gain 7.63dBi, 5.25dBi and 7.12dBi. The proposed design is suitable for wireless, RADAR, satellite, microwave C-band (6.43 GHz-6.72 GHz), X-band (8.85 GHz-9.33 GHz) and (10.50 GHz-13.22 GHz) applications.