Digital Beamforming Demonstration of a Microstrip Antenna Phased Array Feeds (PAF) at 1.25 GHz

We introduce the structure of a radio astronomy phased array feeds (PAF) beamforming demonstrator. In a laboratory environment, we have demonstrated beamforming on a received 1.25 GHz sinusoidal signal and used digital weighting techniques to plot the 2D pattern of the PAF. The radio frequency part of the demonstrator includes a 4 × 4 linearly polarized microstrip antenna array, all of which is connected in series with a low-noise amplifier. The signals from the central 4 × 2 array elements are injected into a radio frequency system-on-chip digital board, which can receive eight inputs with a bandwidth of 512 MHz. Combining the principle of undersampling, the beamforming is completed at a frequency of 1.25 GHz for the offline data, and a 2D image of the beam is plotted using beam scanning technology.