Frequency tunable printed antenna with 90% size reduction for wireless communication applications

Abstract

A compact single layer coaxial probe-fed microstrip antenna with frequency tuning capability is proposed in this paper. The proposed antenna occupies a compact size of only 35 × 35 × 1.6 mm3. The proposed antenna consists of a rectangular defected microstrip structure (DMS) embedded at the rectangular patch and narrow rectangular slot loaded modified ground plane structure (MGS) to create a lower order resonance at 1.85 GHz, which corresponds to 90% miniaturization of the proposed antenna. The lower resonant frequency of the proposed antenna can be adjusted from 4.35 GHz down to 1.85 GHz with 3.59% fractional bandwidth by increasing the length of the slot embedded in the ground plane. The design structure yields an independent control of the desired resonant frequency, gain, fractional bandwidth and compactness of the antenna. By changing the dimension of the ground plane slot, the same antenna geometry supports any wireless communication applications in the frequency range of 1.85 to 4.35 GHz such as 1.92 GHz PCS, 1.9 GHz PHS, 2.4 GHz Bluetooth, 2.6 GHz extended UMTS, 2.8 GHz IMT, 2.4/3.6 GHz WLAN and 2.5/3.5 GHz Wi–MAX etc.