Synthesis approach to design a compact printed monopole filtenna for 2.4 GHz Wi‐Fi application

Abstract

This communication presents a compact low cost filtenna (35 mm × 30 mm) operating in 2.31 to 2.49 GHz spectrum for possible applications pertaining to 2.4 GHz Wi-Fi standards 802.11b, 802.11g, and 802.11n. Initially, two microstrip square open loop resonators are designed to serve as band-pass filters with resonant frequency of 2.4 GHz. Adapting the synthesis approach, the second resonator is replaced by inverted L-shaped monopole antenna designed at 2.4 GHz. The antenna is integrated to filter through coupled line admittance inverter to form a compact module with near zero insertion loss within the proposed operating frequency band, filtenna possess uniform omnidirectional radiation pattern in H-plane and monopole pattern in E-plane, steep skirt at both edges, 7.5% fractional bandwidth, good return loss and low cross polarization characteristics. The simulated design is validated by measurements of parameters of prototype fabricated on FR4 substrate, slight acceptable discrepancy is experienced which can be attributed to fabrication tolerances and variation in material characteristics.