Millimeter-Wave Imaging Arrays

Low cost focal plane imaging arrays are being developed for radar and radiometric applications in the millimeter-wave region. Applications include contraband detection, remote sensing, medical imaging and plasma diagnostics. The use of 1-D imaging arrays significantly reduces mechanical scanning time and cost. Two types of arrays are currently under development for use at frequencies around 100 GHz: hybrid arrays using beam-lead Schottky diodes and wholly monolithic Schottky diodes fabricated on GaAs. Optimum conversion losses on the order of 10-14 dB have been experimentally measured for both types of arrays.

Slot bow-tie (SBT) antennas have been used as the imaging array elements. These antennas exhibit many of the same characteristics as conventional bow-ties, such as wide frequency bandwidths. The advantage of the slot bow-tie is that it is an unbalanced configuration which can be directly output to coplanar waveguide (CPW) and to an external connector, thus greatly simplifying mask and circuit design by removing the need for a balun. The mask layout for a single SBT is shown below. The gold region is metal (either copper or gold) and the grey region is substrate (either Duroid or GaAs). For information on current experimental results, click here.

Single Channel Mask Layout of SBT


Imaging Array Mounted in Shielding Box

[Array Box]


Photo shows a shielding box cover with dichroic plate on top.

On the bottom, a hyperhemispherical lens covers the imaging array. Diode bias circuitry is mounted to the left and right of the array board.

20 Channel Hybrid Imaging Array

[ECE Array]

Send comments to: Peiling Hsu