Wideband Microstrip Nanoantenna Array with Beam Steering Capability

Two logarithmic arrays of microstrip nano-antennas at terahertz frequencies are presented as two subarrays. Because of good properties of microstrip antennas, they are used in many applications. On the other hand, the increasing need for new ways of making smaller electromagnetic devices drives mankind towards nanotechnology. Achieving a wide scan range by nano-antenna arrays with a finite number of elements is one of the design challenges. In the proposed scheme a suitable scan range is extracted by providing a simple layout of the elements. Two feeding ports and only one phase shifter are required for this structure. This antenna is smaller in size compared to many antennas with beam steering capability and comparable and better radiation characteristics. A substrate with a relative dielectric constant of εr=4.4 and a thickness of h=800 nm is used. For good performance at terahertz frequencies, gold metal is used for designing of the structure. Design is done at frequency of 3.3 THz and for wavelength of 91µm. The maximum amount of scanning range with proper level of side lobes and low gain drop while scanning is obtained at φ=30°. In this study by presenting a proper design of nano-patches with insert feeds a beam steering of 28 degrees and gain of 8.72 dB is extracted. In this case, the maximum amount of gain drop during scan is 3.01dB. Also, good impedance matching is obtained and bandwidth is 800 GHz.