The purpose of this paper is to present a complete design and analysis of a new integrated balanced transmitter operated at 4 GHz using microstrip technology. It comprises a 4-GHz two-port negative resistance oscillator and a microstrip-patch antenna resonated at 4 GHz. Three different modules are designed and analyzed. The first one used a Lange coupler as a power splitter while the second and third used a one (two)-section branch couplers. The components of the three modules are designed using full-scale computer simulation program named with MSDES; performed by the author; which takes fully into account all the discontinuities included in the microstrip lines, while the modules are analyzed and optimized using APLAC V7.61 software. The design methodologies of the two-port negative resistance oscillator and microstrip patch antenna are introduced and explained. The analyses of the designed modules show a better efficiency and good performance. The modules give a transmit-antenna gain of 15.7 dB with antenna beam widths 91.7o and 18.2o in E-and H-planes, respectively. The complete schematic diagrams of the transmitter modules are drawn. These modules can be used in satellite communication, Doppler and other radars, active and semi-active seekers, radio altimeters, missile technology, weapon fuzing, manpack equipment, remote sensing, feed elements in complex antennas, satellite navigation receivers, and biomedical radiators.
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