Accurate Analysis and Design of Circularly Polarized Dual-Feed Microstrip Array Antenna using Multiport Network Model

Microstrip Patch Antennas (MPAs) with circular polarization are used in many communication and radar systems. There are several methods and models to analyze and design these antennas. The Multiport Network Model (MNM) is considered one of the best models for MPAs. This model includes several interconnected circuit networks, each of which represents one characteristic of the MPA. The solution of this model is equivalent to the calculation of the input and radiation parameters of the antenna. In this paper, a circularly polarized 2×2 array antenna with sequentially rotated microstrip elements is designed using MNM. In order to produce the circular polarization, besides the sequentially rotation technique, two probe feeds are used in the E-plane and H-plane of each element. These probes are fed by current sources with equal amplitudes and a 90 degree phase difference