Intermodulation Product and Switching Noise Amplitudes of a p-i-n Diode Switch in the UHF Band (Correspondence)

Sicotte, R.L.; Assaly, R.N.

doi:10.1109/tmtt.1970.1127134

Cited by 2 publications

(1 citation statement)

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“…This value was adopted as the criterion for the switch design. 15,16,17 As indicated in Sec. III-B, if the diode is not located at the junction, the RF voltage across the diode is not the same as the RF voltage on the line.…”

Section: A Generalmentioning

confidence: 88%

Development of Uhf Switch for Les-6 Satellite

Assaly¹

1969

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A UHF switch matrix was developed for the LES-6 satellite to electronically despin the antenna beam as the satellite rotated on its axis. Initially, a study was carried out to determine the optimum antenna system and switch configuration for the constraints of satellite geometry and minimal complexity. Two such switch matrices, operated by logic circuits and sun and earth sensors, were used on the satellite, one to excite two adjacent of eight pairs of antenna dipoles, and the other to excite two adjacent of eight pairs of cavity-backed slots. The polarizations of the signals from the dipoles and slots are orthogonal and by adjusting the phase difference to 90°, the satellite will transmit and receive on right-hand circular polarization during normal operation. Furthermore, by squinting the beam formed by two element pairs +11. 25° or-11.25° from the center line of the element pairs, any of 16beams can be formed which are equally spaced in azimuth about the satellite. Each switch consists of three parts, namely, a hybrid to divide the input power into two equal parts, a 2P2T section which switches phase, and two SP4T sections to switch on two antenna pairs. The switch was built in strip transmission line using PIN diodes in series with the inner conductor as the switching element. In its development, a number of conflicting characteristics were required to be optimized. These include the RF characteristics such as VSWR, insertion loss, and isolation; thermal heating of the diodes which determine their reliability; and intermodulation products, switching noise, and random noise which can degrade the satellite receiver performance. It was also necessary to demonstrate that the switch was free from multipactor breakdown and could survive prolonged space radiation. Finally, it had to be proven that the switch had good reliability under the stresses of the rocket launch and through an expected 5-year life in orbit. A detailed discussion of the testing programs is given, as this type of information is not generally available in the open literature.

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Section: A Generalmentioning

confidence: 88%