Circular Microstrip Antenna Array at 5.8GHz Frequency for Unmanned Aerial Vehicles

In the study, an antenna array is designed that has two circular patch elements. Elliptic slots are etched on circular patches than a rectangular piece is added in the center of the slots. The array has a directional radiation pattern with a gain of 11.95 dB. It is resonated at 5.8 GHz ISM band with a return loss value of over -10dB. It is fed by a microstrip line matched to 50 Ω. The array is simulated by ANSYS Electromagnetics Suite, HFSS and parametric optimizations are completed. After determining the optimum parameters, it is manufactured on FR-4 substrate that a thickness of 1.6 mm and a dielectric constant value of 4.4 and a tangent loss of 0.002 by handmade in our laboratory. FR-4 is chosen because of it’ s easy to find and cheap. It is studied in a Bachelor degree final thesis by Ayse Ozge Cinar and her supervisor Seyfettin Sinan Gultekin, and planned to use in an international competition. The 2x1 array is manufactured by using chemical process method that uses hydrochloric acid and hydrogen peroxide solution with a ratio of 3:1. The measurements of S 11 and impedance are obtained with Rohde Schwarz ZVL-13 Vector Network Analyzer in normal room conditions. The array is designed and manufactured as two, for a usage with Unmanned Aerial Vehicle (UAV) communication system on the both receiver and transmitter modules. So, the main aim is obtaining a high gain value over 10dB, and a resonant frequency of near 5.8 GHz. An applicable dimension of the whole array and being light are other necessities. In addition, a long communication distance about 1.5-2 km is needed. The study is started with designing a single circular patch, using formulas from literature. In the second step, with an inspiration of [3] , an elliptic slot is etched on it. Patch and slot parameters are tried with different values in simulations to aim a higher gain. The third step is adding a rectangular piece in the center of the slot with a parametric sweep. For the optimum parameters, the single antenna is also manufactured and measured. After the performance evaluation of this single patch design, the array is created for two antenna elements. The suitable proximity between antenna elements that blocked interference and impedance matching arrangement of the microstrip feedline are completed in simulation media. From comparison of simulation and measurement results, they are compatible with each other and showed that the array design can be used by successfully on communication of unmanned aerial vehicles.