Stan Livingston

A steerable leaky-wave antenna using a tunable impedance ground plane

A steerable leaky-wave antenna is built using a mechanically tunable impedance surface. A horizontally polarized antenna couples energy into leaky transverse electric waves on a tunable textured ground plane. By tuning the resonance frequency of the surface, the band structure is shifted in frequency, which changes the tangential wave vector of the leaky waves for a fixed frequency. This steers the elevation angle of the resulting radiated beam. This steerable leaky-wave antenna can scan over a range of 45/spl deg/ using a mechanical movement of about 1/500 wavelength.

System design and performance of a wideband photonic array antenna

Presented in this paper is an overview of the development of a wideband photonic array antenna. The presentation will focus on the performance of a unique L-band 24 X 4 element conformal array, supported by a photonic true-time-delay beamforming network. A 2-ns pulse was injected into the system and the round trip impulse response was measured to demonstrate the arrays 550 MHz instantaneous bandwidth.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Photonics for phased-array antennas

In this paper, we discuss the applications and also several important system issues: insertion loss, noise figure, dynamic range and cost relating to photonics for wideband phased array antennas. This discussion is based on the work that we did on an L-band Optical Control of Phased Array Project funded by DARPA/Rome Lab. The antenna has been delivered to Rome Lab for further demonstration.

Silica-wavequide optical time-shift network for steering a 96-element L-Band conformal array

We report the demonstration of a 4-bit optoelectronic-switched silica-waveguide time-delay network. Targeted for insertion into a 96-element L-band conformal array, the optical time- shifter provides 16 programmable time-delays in steps of 0.248 nsec. By characterizing its RF insertion phase and synthesized pulse response, we verified that the relative time-delays generated by the waveguides were within 15 psec of their designed value. The antenna patterns obtained with the waveguide-module steering the central column of the phased array demonstrated greater than 50% instantaneous bandwidth for scan angles as wide as +/- 60 degrees.

Photonically controlled airborne SATCOM array designed for the SHF band

We describe the architecture of an airborne SATCOM antenna that is photonically controlled. Specifically, the active array antenna is designed to transmit/receive in the SHF frequency band of 7.25 - 8.4 GHz. We emphasize, in particular, the remoting of the array front-end and the performance enhancements gained by adopting true-time-delay steering via the insertion of photonic technology.

Range test of a photonic conformal array

An L-band 96-element array controlled by photonics was developed and tested. A time shift beamforming network provides a 50% instantaneous bandwidth (850 MHz-1400 MHz). The antenna beam was scanned to +/- 60

Reconfigurable interleaved phased array antenna

DEG without beam squint over the entire bandwidth. A nanosecond impulse response has been measured to demonstrate a range resolution of better than 30 cm for target ID and imaging.