Analysis of helical waveguide
Abstract
Pierce's small-signal theory is used to calculate the dispersion characteristics of the large helical waveguide in the presence of an electron beam. The backward wave gain, of about 2.24 dB/cm, is greater than the forward wave gain, of about 2.17 dB, though the bandwidth of the backward wave is extremely narrow. For a total gain of 30 dB, the bandwidth is 40 percent if the backward waves are ignored, while the onset of the backward wave oscillations limits the bandwidth to five percent. The total gain of the circuit is limited to about 12 dB if the oscillations are not suppressed, and the bandwidth can be as high as 57 percent for such a low gain. It is found that the gain and bandwidth are both larger for the low-order modes, and that the ratio of the backward to forward wave gains, and the number of backward waves excited, are also smaller.
- Publication:
-
IEEE Transactions on Electron Devices
- Pub Date:
- September 1986
- DOI:
- 10.1109/T-ED.1986.22669
- Bibcode:
- 1986ITED...33.1348A
- Keywords:
-
- Bandwidth;
- Broadband Amplifiers;
- Electron Beams;
- Microwave Amplifiers;
- Millimeter Waves;
- Transmission Efficiency;
- Waveguides;
- Electronic Warfare;
- Helical Windings;
- Microwave Oscillators;
- Electronics and Electrical Engineering