Integrated passive front-ends for towed decoys

Summary form only given. The emergence of millimeter wave technologies operating at frequencies outside of traditional electronic warfare bands has been noticed. A critical component of electronic warfare is the towed decoy, which protects its platform from radar guided missiles. The autonomous decoy operates by receiving signals and then emitting appropriate counter-signals to suppress, deceive and/or seduce missiles. Key design features for this platform include wide bandwidth, dual polarization, high power capability, high directivity, low dispersion, low cost and reduced size. This paper discusses the development of wideband passive components for frontend electronic warfare in the aforementioned towed decoys. Specifically, the development of a custom double ridge waveguide cross-section operating over an 18 to 45 GHz band that enables low dispersion and loss is shown. Based on the developed guide cross section, the design of a wideband branch guide coupler and orthomode transducer is demonstrated. The antenna element for the front-end system is a radially compact quad ridge waveguide horn designed for integration with the beamforming components. This horn is able to be designed for specific applications and parameters such as good impedance match, high isolation between orthogonal polarizations, high gain, and constant gain and beamwidth. These components are fabricated using traditional aluminum machining and easily integrated together in the confined space of a towed decoy. The complete dual polarized front-end system has return loss greater than 15 dB, isolation of more than 45 dB, and high power capability of several hundred watts. Relevant conclusions are supported by theory and measurements of all components.