Bandwidth extension of planar antennas using embedded slits for reliable multiband RF communications

In this paper a technique is described to extend the impedance bandwidth of patch antennas without compromising their size. This is accomplished by embedding capacitive slits in the rectangular patch with a truncated ground-plane, and exciting the antenna through a meandered strip-line feed. The proposed antenna was fabricated on standard FR-4 substrate with permittivity of 4.6, thickness of 0.8 mm and loss-tangent of 0.001. The performance of the prototype antenna was verified through measurements. Characteristics of the antenna include an impedance bandwidth of 5.25 GHz (800 MHz-6.05 GHz) for VSWR <2 corresponding to a fractional bandwidth of 153.28%, peak gain of 5.35 dBi, radiation efficiency of 84.12% at 4.45 GHz, and low cross-polarization. These attributes make the antenna applicable for stable and reliable multiband applications in the UHF, L, S and major part of C-bands. The antenna offers advantages of low cost, low profile, ease of manufacturing, durability and conformability.