A Study On Several Key Microwave Components For The Ku-band Phased SOTM System On Board

With the development of society and economy, the demand for satellite communications technology is growing quickly, including the SOTM (Satcom on the Move) system relies on geostationary satellites to establish a stable two-way real-time signal transmission channel. And it’s high width, large capacity, real-time data video transmission make it hugely used in emergency communications mobile video and other fields.The paper described the components and working principle of the SOTM system, analyzed the advantage of a phased SOTM such as tracking flexible, fast response and small size. Then the design ideals of a phased SOTM system based on integrated transceivers antenna technology is proposed. Through using Ku-band frequency communications technology, SINS, GPS and tracking technology combined phased and mechanical scanning beam, the design obtains a low profile, light weight, high scanning speed, etc. And some studies about the key microwave components, for example transmitting and receiving antennas, low noise amplifiers is also done.In SOTM sub-array antenna design, the transmitting antenna sub-arrays were designed with 64 units microstrip patch antenna, and receiving antenna sub-arrays with 16 units patch. Receiving sub-array used edge coplanar microstrip feed, measured with good bandwidth and directional characteristics. Transmitting sub-array used the back coaxial feed, reduced the interference of radiation patch. In addition, another dual-band and dual polarized mircostrip antenna with aperture-coupled feed network is designed at a high-gain. It expand the bandwidth by application of low dielectric constant material and air dielectric layer technology. The Simulation result is that reception gain at 19.67dB, the transmitter gain at 20.28dB and isolation of 34dB, has a high gain and isolation.In microwave circuit design, microwave components such as LNA microwave hybrid circuits and power divider were designed, The two stage low-noise microwave hybrid circuits which build by GaAs microwave monolithic low-noise amplifier chip, and matched band-pass and low-pass filter with good performance that can be used to put the receiver channels to meet the primary signal processing? The four-ways Wilkinson power divide designed by three-quarters wave length matching and half-wavelength microstrip of port connection technology make a high isolation, amplitude and phase coherence. Finally, it present an integrated transceiver circuit antenna sub-array module applied phased SOTM, the advantage of the module can be reduced the signal interconnection between antenna with the control circuit, the beam forming network, the signal processing circuit and power supply system components and improve the level of electromagnetic compatibility, maintainability and scalability.