Demonstration of a wide-band fiber-optic nulling system for array antennas

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

“…When realized optically, they can offer wideband, continuously tunable operation, and can be made independent of the operating RF frequency [13][14][15][16], allowing squint-free beamsteering and controllable nulls positioned on large percentage bandwidths [4,[16][17][18][19][20]. Multibeam capability can also be easily added to a beamformer, without dramatically increasing the network complexity, by using multiple optical wavelengths (as shown in [18,[21][22][23][24]).…”

Proceedings of IEEE International Conference on Phased Array Systems and Technology Held in Dana Point, California on 21-25 May 2000

“…Due to the high time-delay resolutions attainable, the beamformer is readily adaptable to any frequency range of interest with operation in the mm-wave regime recently demonstrated [17]. Wideband nulling is also straightforward to incorporate due to the continuous, analog nature of the time-delay generation [18]. The systems have exhibited excellent amplitude and phase tracking characteristics of -0.1 dB rms and 3.5° rms over a 2 GHz bandwidth.…”

“…Table 1 gives various ECM threats and the electronic counter-counter measures (ECCM) to them. The countermeasure to the sidelobe barrage jammer is a sidelobe canceller (SLC) [15][16][17][18]56]. MIT Lincoln Laboratory demonstrated a jammer cancellation of 50 dB for an L-band linear array of 32 elements [19,20].…”

“…At the core of the test-bed concept are the four ONR funded low band and high band transmit and receive array apertures. Fundamental to the selected AMRFS architecture is the physical separation of receive and transmit and the partitioning of the 1-20 GHz frequency coverage into two bands, low band (1-5 GHz) and high band (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Both receive arrays include the receive array subsystem, RF down-conversion and digital receivers and local processing and control necessary to support simultaneous and time-interleaved multi-function receive functions from RF through to digitized I&Q samples of the received environment.…”

Wide-band nulling system for antenna array based on a photonic microwave filter and optical delay lines

“…Therefore, this optical system will be characterized by its high flexibility in controlling, in a totally independent way, the wide-band null direction as well as the phased array steering direction. To achieve this goal, in [11] a wide-band fiber-optic nulling system for array antennas based on a dispersive prism technique was demonstrated. Despite being simpler than previous optically wide-band proposals [12][13][14], this technique requires two optoelectronic conversions what is a severe impairment to power budget.…”