In-Situ Assessment of Array Antenna Currents for Real-Time Impedance Tuning

Impedance tuning has shown promise to maximize output power, gain, or efficiency for transmitter amplifier devices in changing frequency or array environments. Using impedance tuning in phased-array elements, however, has a significant and dynamically changing impact on the transmitted array pattern. To assess the impact of impedance tuning operations on the array pattern, this paper presents a simple method to monitor the antenna input current in real time, allowing optimizations that attempt to preserve the array pattern while achieving goals of increased power, gain, or efficiency. The real-time monitoring of current provides many advantages over traditional array calibration methods in situations where the array element chains can change significantly in magnitude and/or phase during operations.