| Title |
Quadrature Directional Coupling Method for Precise RF Power Measurement |
| Authors |
- B. Du, G. Huang, L. Lin, Y.T. Liu, Z. Zhao
USTC/NSRL, Hefei, Anhui, People's Republic of China
|
| Abstract |
The directional coupler is used in the RF transmission and distribution system of accelerator, to measure the forward and backward power. Due to the finite directional isolation of the coupler (20-30dB normally), the crosstalk exists between the bi-directional coupling output signals. For the typical isolation of 26dB, if the bi-directional crosstalk signals are in- or anti- phase, the error of input or reflected power measurement is 10% in case of total reflection, whilst the error of reflected power measurement is 100% in case of VSWR 1.1. A method of quadrature directional coupling measurement is developed to solve the isolation problem. A pair of directional couplers with 90° phase difference are employed to measure the RF power. The influence of the directional crosstalk would be reduced significantly by processing the measurement data. The prototype of quadrature directional couplers is constructed to verify this method. The results showed that the measurement accuracy of quadrature coupler pair after data process is better than 2% for forward measurement, even if the error of single coupler is over 6%. The paper also analyses the error caused by non-ideal quadrature.
|
| Paper |
download MOPMY016.PDF [0.449 MB / 3 pages] |
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| Conference |
IPAC2016, Busan, Korea |
| Series |
International Particle Accelerator Conference (7th) |
| Proceedings |
Link to full IPAC2016 Proccedings |
| Session |
Poster Session |
| Date |
09-May-16 16:00–18:00 |
| Main Classification |
07 Accelerator Technology |
| Sub Classification |
T08 RF Power Sources |
| Keywords |
coupling, radio-frequency, feedback, controls, experiment |
| Publisher |
JACoW, Geneva, Switzerland |
| Editors |
Christine Petit-Jean-Genaz (CERN, Geneva, Switzerland); Dong Eon Kim (PAL, Pohang, Republic of Korea); Kyung Sook Kim (PAL, Pohang, Republic of Korea); In Soo Ko (POSTECH, Pohang, Republic of Korea); Volker RW Schaa (GSI, Darmstadt, Germany) |
| ISBN |
978-3-95450-147-2 |
| Published |
June 2016 |
| Copyright |
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