FSS embedded high gain ‘N’ shaped miniaturized broadband antenna

Abstract

This research work represents a broadband (3.3 GHz − 17.85 GHz) high gain miniaturized (16 mm × 24 mm × 1.6 mm) microstrip patch antenna. Initially multiband property is achieved through ‘N’ shaped radiating patch surface and ‘I’ shaped ground plane surface. Finally broadband property is attained through better impedance matching by modifying feeding structure with a single step matching staircase structure. The presented antenna shows large −10 dB impedance bandwidth of 14.55 GHz with a percentage bandwidth of 138 %, Bandwidth Dimension Ratio (BDR) of 2970 and a peak gain of 4.45 dBi at 9.5 GHz. By embedding FSS (Frequency Selective Surface) structure having FSS unit cell dimension of 13 mm × 13 mm × 1.6 mm with the antenna at suitable distance, antenna gain has been elevated successfully across the entire operating frequency range (3.25 GHz–17.8 GHz). FSS coupled antenna exhibits highest gain improvement of 7.5 dBi at 3.5 GHz and peak gain of 9.1 dBi at 9.3 GHz. The FSS integrated antenna structure operates with elevated gain (peak gain of 9.1 dBi at 9.3 GHz) across the entire operating frequency range (3.25 GHz–17.8 GHz). All inclusive volume of the presented FSS coupled antenna is 52 mm × 52 mm × 21.2 mm, which can be successfully utilized in high gain broadband wireless applications. The antenna patch area miniaturization is calculated as 65 % with respect to lowest frequency of operation. The proposed FSS and antenna are developed and simulated by utilizing CST Studio Suite Software and equivalent circuit of the presented antenna is simulated utilizing ADS software. Both FSS and antenna are fabricated using inexpensive FR 4 substrate (1.6 mm thick, relative dielectric constant of 4.4 and loss tangent of 0.02) and Standard Microwave Test Bench is used to validate the antenna and composite antenna structure simulation results.