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a schematic diagram of the electric eld vector shown in Fig. 2. e electric eld vector of the APAA at initial phase in the REV method is . Here, if the phase of element n is changed by the phase shier installed in it, the synthetic electric eld vector is obtained. Because the relative power of synthetic electric eld vector changes like a cosine function, the relative electric eld vector of the element, , can be obtained from the amplitude and initial value, by tting the obtained data to a cosine function. Also, the compensation phase to maximize antenna gain can be derived from the peak value of the cosine function.Here, the relative phase of an element means the dif-ference of the phases and , φn – φ0. e compensa-tion phase is the angle (Δ0) formed by the direction of the maximum synthetic electric eld vector and the electric eld of a certain element when the concerned element and electric eld vector are rotated. at is, when the phase of the concerned element is rotated corresponding to the compensation phase, the synthetic electric eld contributed by the concerned element reaches the maximum. By apply-ing this method to all the elements, the antenna gain reaches the maximum.4Practical method4.1Retrieval of REV dataOn-orbit REV of WINDS was measured with the conguration shown in Fig. 3. REV was performed by the element phase control command by JAXA, shiing the phase of receiving or transmitting the APAA phase of WINDS 360° divided by 11.25° of the minimum step of phase setting. e REV of the receiving APAA was per-formed by the xed phase of the beam of the transmitting APAA to the Kanto area. e REV of the transmitting APAA was performed by the xed phase of the beam of the receiving APAA to the Kanto area. e satellite tran-sponder is set to a non-regenerative transponder mode.As there are two systems of transmitting the APAA and receiving the APAA, REV of the WINDS APAA was per-Initial Electric Field Vector of ：∅Electric Field Vector of REV：Compensation Phase of Element #n :Δ0Electric Field Vector of Element #n:∅Maximum Composite ElectricField VectorElectric Field Vector of Element #1:∅Relative Phase of Element #n: ∅-∅0FiF2　Electric field vector of REVRX AMP 1RX PS 1aRX AntennaRX PS 1bRX AMP 2RX PS 2aRX PS 2bRX AMP128RX PS 128aRX PS 128bRX BFN aRXBFN b#2#128TX AMP 1TX PS 1aTX PS 1bTX AntennaTX-1BeamTX-2BeamTX BFN aTX BFN bTX AMP 2TX PS 2aTX PS 2bTXAMP 128TX PS 128aTX PS 128b#1#2#128RX-1BeamRX-2BeamD/C, U/C,IF SW#1FiF1　APAA block diagram3 Ultra-High-Speed Satellite Communication Technology128　　　Journal of the National Institute of Information and Communications Technology Vol. 64 No. 2 (2017)