K-to-W-band phased array antenna technology

Abstract

IntroductionA new phased array antenna (PAA) has been designed with frequency coverage from K-to W-band. This approach takes advantage of new 3D lithographic manufacturing techniques and Harris' Current Sheet Antenna (CSA) to cover 16-110 GHz from a single aperture. In this paper, analysis results will be presented, providing greater than 50% radiation efficiency over the entire instantaneous bandwidth and good scan performance to 60 degrees. To the author's knowledge, this is the first PAA capable of continuous operation from 16-110 GHz. This exciting new technology will be applicable to future avionics systems with direct integration to transmit and receive RF photonic back-ends. Technical DiscussionThere is a growing need for millimeter wavelength (mmW) antennas as outlined by recent military programs (DARPA Hotspots, DARPA MFRF, and ONR D&I BAA 11-006) and commercial applications [1], which range from RADAR to communications. These future systems, when applied to avionics platforms, will require rapid antenna beam pointing that is only possible with a PAA. To meet this demand, wide bandwidth PAA topologies that are manufacturable at mmW frequencies are needed.Several approaches exist to cover multiple octaves of bandwidth [2-4]. However, these approaches have yet to be applied to mmW frequencies. Instead, the published literature for mmW PAAs has focused on narrow bandwidth, resonant type elements such as patch and slot antennas [5].In order to demonstrate a multi-octave PAA at mmW frequencies, one of the lower frequency antenna topologies must be migrated higher in frequency. Unfortunately, each of the aforementioned multi-octave technologies lends itself to either fabrication on or surrounded by low permittivity substrates, while current work at mmW frequencies has focused on lithographic fabrication techniques on high permittivity substrates (semiconductors, ceramics, or polymer based) or in waveguide, which is inherently narrow band. We believe that a variant of the CSA, optimized for 3D lithographic fabrication in copper, using Nuvotronics PolyStrata process, is the best way to achieve multi-octave bandwidths at mmW frequencies. 1 mm 1.5 mmFigure 1. Predicted Radiation Efficiency Of The 16-110 GHz CSA And Unit Cell Model.