A SIW Cavity Backed Dual Band Filtenna for X-Band and Ku-Band Applications with Controllable Radiation Nulls

In this paper, a Substrate Integrated Waveguide (SIW) cavity backed dual band filtenna (DBF) is presented for X-band and Ku-band applications. A rectangular slot is etched out from the cavity to design the antenna, which creates a radiation null (RN) in the lower edge of the frequency. Characteristics of filtenna is achieved by inserting a rectangular open loop slot (ROLS) in the bottom of the radiator. ROLS creates another RN at the upper edge of frequency. The Dual band characteristics is achieved by inserting another rectangular slot in the radiator. One more ROLS is inserted above the slot to sharpen the selectivity at the lower edge. The proposed DBF has impedance bandwidth (IBW) of (8.4%) with (10.3 dBi) maximum gain is reported in X-band while (7.9%) IBW and (8.9 dBi) maximum gain in Ku-band. A good agreement between simulated and desired results is achieved. The proposed DBF is compared with the existing literature which propagates this to be a good candidate for multi-frequency applications.