Conceptual Study of Analog Baseband Beam Forming: Design and Measurement of an Eight-by-Eight Phased Array

We report on the design and measurement of an eight-by-eight modular phased array that uses analog quadrature baseband phase shifters. The array is designed for 2.4 GHz and has a few MHz of bandwidth. Though for such frequency, bandwidth and number of elements, digital beam forming is still feasible with contemporary analog-to-digital converters (ADC), the design is a proof of concept for analog baseband beam forming and shows that this technique will work at frequencies and bandwidths beyond ADCs capabilities. Besides covering the architecture, implementation and the measurement of the array, the calibration is discussed extensively, as this is an inevitable step in activating the antenna.