Analysis of Rectangular Microstrip Array Antenna Fed Through Microstrip Lines with Change in Width

This paper deals with a detailed investigation of a microstrip array antenna with step discontinuities at its feed line has been presented. In the proposed configuration, antenna arrays at 2.45 GHz are designed, simulated, and fabricated to demonstrate the concept of step discontinuities in the feed lines. A four-element rectangular patch array is fully characterized, and its performance is critically assessed for no step, single step, and double step microstrip feed lines. The return loss S11 [dB] is better for microstrip array antennas with double step feed lines than array antennas with no step and single step feed lines. Impedance matching and higher isolation between the patches and feed lines were appropriate using step discontinuities at the feed lines. FR4 substrates were used to design, simulate, and fabricate the microstrip array antennas. The simulated S11 [dB] for no-step feed lines, single-step feed lines, and double-step feed lines for rectangular microstrip array antennas are −8.78 dB, −16.48 dB, and −17.15 dB, respectively. Prototypes of these antennas are then fabricated and measured to validate the analysis and design experimentally. The simulated and measured results agree with each other.