System integration and radiation pattern measurements of a phased array antenna employing an integrated photonic beamformer for radio astronomy applications

Abstract

In this paper we describe the system integration and the experimental demonstration of a photonically beamformed four-element receiving array antenna for radio astronomy applications. To our knowledge, the work described here is the first demonstration of the squint-free, continuously tunable beamsteering capability offered by an integrated photonic beamformer based on optical ring resonator true-time-delay units, with measured radiation patterns. The integrated beamformer is realized in a low loss, complementary metal-oxide-semiconductor (CMOS) compatible optical waveguide technology. The measurements show a wideband, continuous beamsteering operation over a steering angle of 23.5 degrees and an instantaneous bandwidth of 500 MHz limited only by the measurement setup.

Integrated microwave photonics

“…For practical applications like satellite communications, a wideband continuously tunable beamformer is required. Such beamformer based on cascaded tunable ORRs was proposed by the researchers in the University of Twente . In , a state‐of‐the‐art ring resonator‐based 1 × 8 beamformer chip has been proposed.…”

“…(b) Photograph of the packaged chip. , courtesy of the OSA. (c) Functional design of the 16 × 1 photonic beamformer showing the ORR delay elements and the sideband filter.…”

Programmable optical processor chips: toward photonic RF filters with DSP-level flexibility and MHz-band selectivity

“…For microwave photonic solutions to the traditional RF functions in this area such as RF filters and beamformers for phased array antennas [69][70][71][72][73], optical filters that are able to provide MHz-band frequency selectivity can play an enabling role in satisfying the standard system requirements. One potential application of high interest is RF filters for input and output multiplexers (IMUXs and OMUXs) of satellite transponders that currently rely on bulk electronics.…”

RF Engineering Meets Optoelectronics: Progress in Integrated Microwave Photonics

“…A complete beamformer based on ORRs arranged in a binary-tree network architecture was demonstrated in [68]- [73], with [73] fabricated in TriPleX waveguide technology. Delays up to 1.2 ns were shown over a bandwidth of 2.5 GHz for K u -Band satellite communication applications [71], [72], [74] and radio astronomy [75], for which a system demonstration of squint-free beamsteering of a four-element array was shown. More advanced hardware compressive architectures featuring multiwavelength operation and exploiting the frequency periodicity of ORR filters have recently been reported [75], with instantaneous bandwidths in excess of 8 GHz.…”

“…Based on a limited number of fundamental building blocks, i.e., optical waveguides, phase shifters, and directional couplers, complex tunable filters have already been fabricated and demonstrated, such as MZIs, ring resonators with add and drop ports, and more complex optical filters based on a combination of those with flattened passband and sharp transition bands [36], [115]. Complex microwave photonic signal processors have been demonstrated with this technology, i.e., optical beamformers [72] and high-selectivity microwave photonic filters [116]. An example of a 16 # 1 beamformer chip is shown in Figure 14 and illustrates well the level of complexity that is possible through the use of several cascaded ring resonator elements [117], [118].…”