Javad kiyani Harchegani - Department of Computer and Electrical Engineering, Tarbiat Modares University, Tehran, Iran.
Bijan Abbasi Arand - Department of Computer and Electrical Engineering, Tarbiat Modares University, Tehran, Iran.

Reflectarray antenna with the advantages such as low profile and high directivity is a good candidate to be replaced for conventional high profile reflector antenna and complex feed network phased array antenna. There are different types of elements used as reflectarray antenna unit-cell. The main key in designing a unit cell is the capability of creating required phase shifts to compensate for the different lengths of the paths from the feed to each element on the array surface. The simplest method to get the phase shift is changing the dimensions of the radiating element which narrows the operating frequency of the array. Here we proposed a new microstrip element by the combination of a patch antenna and a circular slot. Phase shifts are obtained through the variable length of the slot. The unit-cell is designed at the frequency of ۹ GHZ. We show the efficacy of the proposed unit-cell as a reflectarray radiating element through numerical EM simulation conducted in Ansoft HFSS software. The future work will consider designing the array structure using this element and improving the performance of the proposed element.

Reflectarray Antenna, Microstrip Patch, Variable slot length.