Monopulse Special Antennas Patent No. 4721-959 In addition to standard prime focus, Cassegrain, and horn-type antennas, there are unique system applications that require special antennas. Monopulse and conical scan antennas are available for precise tracking requirements. Remote polarization diversity is available on many antennas including monopulse to provide versatility in transmitting or receiving complete polarization information. Light-weight antennas and arrays are available for aircraft applications. Multiple beam and beam-scanning antennas are available for navigation and radar imaging. Monopulse Antennas Alpha provides many unique antennas in a monopulse configuration for precision tracking and _ high resolution applications from 5 to 140 GHz. Alphas design is a classical two plane, amplitude comparison monopulse in which the sum (2) and difference (A) signals are formed at RF frequencies. In the final monopulse processing, the error signals can be generated and formed in the IF receiver section. The sum and difference modes are formed in a monopulse comparator which consists of four hybrid junctions, appropriate phase trimmers and interconnecting waveguides. These signals are coupled to Alphas multimode scalar feed horn through a sensitive resonant cavity. In many applications, the multimode monopulse scalar feed assembly can be combined with Alphas Cassegrain design. Other applications may use the monopulse scalar feed assembly with a lens or prime focus parabolic antenna. In a wide beam monopulse requirement, the scalar feed assembly may be used as a far-field horn antenna. Alpha has also provided monopulse antenna assemblies with multiple polarization capabilities. Multiple polarizations include dual linear orthogonal, circular, dual circular orthogonal, linear/circular selectable, and complete remote selectable which provides linear vertical, linear horizontal, right circular, and left circular polarization. Measured performance data of several monopulse antennas are given for frequencies of 9, 35, 50, 70, and 94 GHz. Many additional frequencies and sizes are available upon request. Each monopulse antenna is completely tuned and tested at the specified frequency. Complete test data including gain, radiation patterns, VSWR, and isolation are provided with each antenna. ALPHA INDUSTRIES, INC. TRG GROUP 20 SYLVAN ROAD, WOBURN, MA 01801Special Antennas Typical Monopulse Antenna Performance Values Frequency: 8.5-9.5 34.5-35.5 51.5-54.5 69.0-71.0 93.5-94.5 Reflector 120 96 36 18 18 Diameter (in) Polarization Linear Linear Linear Linear Linear Sum Port Half Power Beamwidth () 0.8 0.25 0.45 0.65 0.6 Sidelobes, Nom. (dB) -18 -18 ~18 -18 -18 Feed Insertion Loss Max, Any Port (dB) 0.5 1.0 15 1.0 2.5 Net Gain, Min. (dBi) 47 54 50 46 46 VSWR, Max 1.5 15 15 15 1.7 Difference Port (Relative to sum Peak) Half Power Beamwidth () 1.76 0.55 1.0 1.45 4.35 Sidelobes, Nom. (dB) -18 -18 -18 -18 -18 Amplitude, Nom. (dB) 4 4 4 4 ~4 Max. Peak Variation (dB) 1.0 1.0 1.0 1.0 1.0 Null Depth, Min. (dB) 35 30 -30 -25 ~25 VSWR, Max 1.7 1.7 1.7 1.7 2.0 Isolation 30 30 25 20 20 1. Remote linear/circular selectable options are available. 1-62 ALPHA INDUSTRIES, INC. TRG GROUP 20 SYLVAN ROAD, WOBURN, MA 01801