Miniaturization of a bow-tie antenna with textured dielectric superstrates

Use of high permittivity dielectric constants is known to reduce the antenna resonance frequency but also introduce side effects such as reduced gain and bandwidth. This paper presents a miniaturization scheme for a 15 cm (6 inch) square cavity backed bow-tie antenna using a textured dielectric superstrate. The proposed design has an operational frequency around 300 MHz making the antenna size 0.15 λ₀. Given the expected gain reduction with miniaturization, the challenge is to obtain large bandwidth while maintaining a gain of 2-4 dBi. Here, we show that by using textured superstrates, we can increase bandwidth and still maintain good gain. We present the developed design and pertinent simulations using the finite element-boundary integral (FE-BI) method.