ASIP development of a real-time control module for a retrodirective antenna array

Abstract

Electronically steerable antenna arrays become attractive due the possibility of simultaneously steering the main lobe in the desired direction and suppressing side lobes only by means of electronic control of excitation currents, hence avoiding mechanical components. However, this type of antenna requires intensive calculation for setting the excitation current of each array element in order to shape the radiation pattern for retransmission, thus demanding a dedicated hardware. This work reports the development of a digital control module for a retrodirective antenna array based on a customized dedicated microcontroller called PAMPIUM, which has been implemented on FPGA, aiming real-time response and low power consumption. A methodology for generation of optimized hardware in terms of area, power efficiency and performance is discussed. A design tool to provide the user with a practical and intuitive environment has been developed, which allows simulating and assessing statistics about execution and performance of the designed architecture. The developed digital control module is capable of updating the current coefficients of an eight-element antenna array in less than 1 s with a power consumption of 5.3 mW for beamsteering angles from 0° to 60°. The proposed methodology allows the demonstration of full efficiency of a retrodirective antenna array system.