Speaker
Description
We present a custom-designed directional coupler intended for use in phase reference distribution systems for linear particle accelerators. Such systems require low phase drift, handle relatively high-power signals, and often are subjected to ionising radiation. The coupler is designed for an operating frequency of 162.5 MHz, 25 dB coupling, and input power in the range of 40-50 dBm. The prototype achieves mainline insertion loss below 0.03 dB and directivity above 35 dB. Its physical length of 21 cm (approx. 8¼") is well below quarter-wavelength, making it relatively compact. To allow use of the coupler near the beam-line, radiation-sensitive materials such as PTFE are avoided in the construction. The internal structure is realized on a printed circuit board (PCB), which allows for ease and high repeatability of manufacturing. Importantly, the PCB dielectric serves mainly as a mechanical support for the copper pattern and its influence on the electromagnetic field is minimized. This helps reduce phase drifts due to the sensitivity of dielectric permitivity to temperature changes.
| Abstract Category | Timing and Synchronization |
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