Shinichi Kozono

On-orbit measurement of phased arrays in satellites by rotating element electric field vector method

This paper discusses the measurement of the excitation amplitude and phase of each element antenna of phased arrays in satellite orbit. In a phased array, the excitation amplitude and the phase of each element antenna deviate from the desired values, due to the nearby satellite structure, the error of attachment to the satellite, and thermal deformation in the orbit. The errors in the amplitude and the phase must be known for beam scanning and the synthesis of various antenna patterns. The rotating element electric field vector method is useful in measuring the amplitude and the phase of phased arrays. In this method, the amplitude and the phase of the element antenna can be determined simply by varying the phase of the element antenna by a phase-shifter and measuring the amplitude change of the electric field as a result of composition by the array. This is suited to the measurement of phased arrays in satellite orbit, where direct measurement of the phase is difficult. In this study, the above method is used to measure the excitation amplitude and phase of the phased array installed on Engineering Test Satellite VI in orbit. Based on the measured phase, the phase is corrected to realize the designed value. The accuracy of the beam directivity is examined and the validity of the measurements is evaluated.

Initial Performance of an Onboard Packet Switch for High-Data-Rate Mobile Satellite Communications

The use of an onboard switch results in a more effective multi-beam satellite communications system. The National Institute of Information and Communications Technology has been studying a mobile satellite communications network, and developing an onboard packet switch. A compact mobile earth station that can be installed in mobile systems or easily carried anywhere has been assumed for this communication system. This system is used to realize mobile satellite communications networks with a signal transmission rate of more than several hundred kilobits per second. The onboard packet switch functions as bridges operating in the data link layer of the open systems interconnect networking model. When the switch is located in a satellite, the satellite can be regarded as the central hub. One beam of the mobile link corresponds to one segment of the network. The bridges’ learning process is carried out between the beams, and the switching system builds and maintains tables with media access control address information. The onboard packet switch was installed in the Engineering Test Satellite Eight, which was launched by the H-IIA rocket in December 2006. An initial test in the geostationary satellite orbit has already been conducted. The results of the test show that the onboard packet switch satisfied system requirements.

A Subsystem of Electromagnetic Wave Radiation and Propagation Estimation Using HTS Receiving Filters for S Band

A process is provided for making a multilayer integrated circuit substrate having improved via connection. A first layer M1 of chrome-copper-chrome is applied to a ceramic substrate and the circuits etched. A polyimide layer is then applied, cured, and developed and etched to provide via holes in the polyimide down to the M1 circuitry. The top chrome is now etched to expose the M1 copper in the via holes. A second layer M2 of copper-chrome is evaporated onto the polyimide at a high substrate temperature to provide a copper interface at the base of the vias having no visable grain boundaries and a low resistance. M2 circuitization is then carried out.

Antenna pattern measurement of the S-band active phased array on the ETS-VI

Two measurements of the on-board S-band multibeam active phased array antenna (SIC) on the Japanese Engineering Test Satellite-VI (ETS-VI) in space are presented. One is an antenna pattern measurement of the SIC making use of the spin of the ETS-VI. The other is measurement of the excitation amplitude and phase of the individual antenna elements of the SIC by means of the rotating element electric field vector method. (Author)