Uniplanar CPW-fed slot/microstrip antenna for X-band applications

There are a number of applications in which wireless (communication or radar) systems require the use of compact uniplanar antennas. Particular application areas are those where antennas have to be combined with microwave monolithic integrated circuits [1]. If these antennas are to be used at upper microwave or millimetre wave frequencies, it is desirable that they are fed from a coplanar waveguide (CPW). The reason is that this waveguiding structure allows for easy integration of such antennas with RF electronics operating at upper microwave or millimetre-wave regions. When compared with other printed radiating elements, CPW-fed antennas possess the advantage of not only having a broad bandwidth, but also a smaller mutual coupling between their feeding lines and the remaining RF circuitry. For these reasons, printed antennas with coplanar waveguide (CPW) feeds have attracted attention for many years [2-6].