Brian J. Herting

Measured Results of a Dual-Band Dual-Mode Millimeter Wave Analog EMXT Waveguide Phase Shifter Electronically Scanned Antenna (ESA)

A proof-of-concept dual-band dual-mode 25/44-GHz electronically scanned array (ESA) is realized using electromagnetic crystal (EMXT) waveguide sidewalls developed at the Rockwell Scientific Company (RSC) and Rockwell Collins, Inc. (RCI). A 15-element one-dimensional (1-D) linear array was tested at the RCI near field antenna range to show frequency independence and beam steering capability. The results of these tests are presented herein.

Electromagnetic bandgap waveguide (EBG) phase shifters for low cost electronically scanned antennas (ESA)

Tunable electromagnetic bandgap (EBG) structures are used as variable surface impedance in the sidewall of waveguides to provide three generations of agile analog phase shifters for low cost ESA applications. A design methodology is discussed using a periodic unit cell approach. Three unique millimeter wave varactor diodes (heterojunction barrier varactor, Schottky varactors and flip chip Schottky varactor diode) have been developed. They have been introduced in monolithic form for the first two-generations and flipchip varactors for the last generation of EBG phase shifters. Results from each generation are reported with a phase shift of 36 to 16.8 deg/mm and the lowest insertion loss of 0.3 dB/mm at 38 GHz. A surface impedance model predicts the increase in the inductance/capacitance ratio of the unit cell components provides the lowest insertion loss. This is validated from the measured results from the three generations of the phase shifter circuits. Our results indicate that the approach of the electronically tuned EBG waveguide phase shifters could provide the low cost-high performance components for an ESA architecture without the need for TR modules.

Low Profile, Frequency Scanned Weather Radar Waveguide Feed Manifold

In this paper, a novel approach to achieving a low profile, low loss feed manifold for center-fed frequency scanned radar systems has been presented. Inclusion of a reactive buffering region, allowing independent control of the slot in each waveguide, has been shown to increase degrees of freedom in design efforts and decrease mechanical tolerance requirements, thus permitting the use of standard low cost machining practices