A novel optical beamformer concept is introduced that can be used for seamless control of the reception angle in broadband wireless receivers employing a large phased array antenna (PAA). The core of this beamformer is an optical beamforming network (OBFN), using ring resonator-based broadband delays, and coherent optical combining. The electro-optical conversion is performed by means of single-sideband suppressed carrier modulation, employing a common laser, Mach-Zehnder modulators, and a common optical sideband filter after the OBFN. The unmodulated laser signal is then re-injected in order to perform balanced coherent optical detection, for the opto-electrical conversion. This scheme minimizes the requirements on the complexity of the OBFN, and has potential for compact realization by means of full integration on chip. The impact of the optical beamformer concept on the performance of the full receiver system is analyzed, by modeling the combination of the PAA and the beamformer as an equivalent two-port RF system. The results are illustrated by a numerical example of a PAA receiver for satellite TV reception, showing that-when properly designed-the beamformer hardly affects the sensitivity of the receiver.

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Measurements have been performed in a Vibrating Intrinsic Reverberation Chamber (VIRC). This chamber has varying angles between wall, floor and ceiling. Inside the VIRC a diffuse, statistically uniform electromagnetic field is created without the use of a mechanical rotating mode stirrer. In comparison to other reverberation chambers the VIRC displays an improved low frequency behavior, enabling faster, cost effective testing and allows for in-situ measurements. Several measurement results obtained in the VIRC are presented in this paper, such as the change in resonance frequenccy, the stirring ratio and the power density function.

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