History of changes to: Harmonic and higher order mode mm-wave klystrons
Date Action Change(s) User
Nov. 27, 2023, 2:12 p.m. Added 35 {"external_links": []}
Nov. 20, 2023, 2:02 p.m. Added 35 {"external_links": []}
Nov. 13, 2023, 1:33 p.m. Added 35 {"external_links": []}
Nov. 6, 2023, 1:31 p.m. Added 35 {"external_links": []}
Aug. 14, 2023, 1:30 p.m. Added 35 {"external_links": []}
Aug. 7, 2023, 1:31 p.m. Added 35 {"external_links": []}
July 31, 2023, 1:33 p.m. Added 35 {"external_links": []}
July 24, 2023, 1:35 p.m. Added 35 {"external_links": []}
July 17, 2023, 1:34 p.m. Added 35 {"external_links": []}
July 10, 2023, 1:25 p.m. Added 35 {"external_links": []}
July 3, 2023, 1:26 p.m. Added 35 {"external_links": []}
June 26, 2023, 1:25 p.m. Added 35 {"external_links": []}
June 19, 2023, 1:27 p.m. Added 35 {"external_links": []}
June 12, 2023, 1:29 p.m. Added 35 {"external_links": []}
June 5, 2023, 1:33 p.m. Added 35 {"external_links": []}
May 29, 2023, 1:27 p.m. Added 35 {"external_links": []}
May 22, 2023, 1:28 p.m. Added 35 {"external_links": []}
May 15, 2023, 1:31 p.m. Added 35 {"external_links": []}
May 8, 2023, 1:36 p.m. Added 35 {"external_links": []}
May 1, 2023, 1:27 p.m. Added 35 {"external_links": []}
April 24, 2023, 1:34 p.m. Added 35 {"external_links": []}
April 17, 2023, 1:29 p.m. Added 35 {"external_links": []}
April 10, 2023, 1:24 p.m. Added 35 {"external_links": []}
April 3, 2023, 1:26 p.m. Added 35 {"external_links": []}
Jan. 28, 2023, 11:08 a.m. Created 43 [{"model": "core.projectfund", "pk": 25809, "fields": {"project": 2998, "organisation": 21, "amount": 43770, "start_date": "2013-02-01", "end_date": "2014-01-31", "raw_data": 42439}}]
Jan. 28, 2023, 10:51 a.m. Added 35 {"external_links": []}
April 11, 2022, 3:46 a.m. Created 43 [{"model": "core.projectfund", "pk": 17914, "fields": {"project": 2998, "organisation": 21, "amount": 43770, "start_date": "2013-02-01", "end_date": "2014-01-31", "raw_data": 18481}}]
April 11, 2022, 3:46 a.m. Created 41 [{"model": "core.projectorganisation", "pk": 68114, "fields": {"project": 2998, "organisation": 1736, "role": "PP_ORG"}}]
April 11, 2022, 3:46 a.m. Created 41 [{"model": "core.projectorganisation", "pk": 68113, "fields": {"project": 2998, "organisation": 543, "role": "COLLAB_ORG"}}]
April 11, 2022, 3:46 a.m. Created 41 [{"model": "core.projectorganisation", "pk": 68112, "fields": {"project": 2998, "organisation": 4596, "role": "COLLAB_ORG"}}]
April 11, 2022, 3:46 a.m. Created 41 [{"model": "core.projectorganisation", "pk": 68111, "fields": {"project": 2998, "organisation": 32, "role": "LEAD_ORG"}}]
April 11, 2022, 3:46 a.m. Created 40 [{"model": "core.projectperson", "pk": 42132, "fields": {"project": 2998, "person": 4948, "role": "COI_PER"}}]
April 11, 2022, 3:46 a.m. Created 40 [{"model": "core.projectperson", "pk": 42131, "fields": {"project": 2998, "person": 5019, "role": "PI_PER"}}]
April 11, 2022, 1:47 a.m. Updated 35 {"title": ["", "Harmonic and higher order mode mm-wave klystrons"], "description": ["", "\nThe Klystron is a well-known, high efficiency amplifier, with a simple structure and scalable dimensions. It is typically designed with cylindrical reentrant cavities in the fundamental mode. However as the frequency of the device increases the size of the structure decreases. At mm-wave frequencies this leads to two problems: \n\n1) Manufacturing the complex small scale structures. \n2) The gap voltage decreases as the gap gets shorter leading to less gain.\n\nMost mm-wave klystron concepts reported in the literature are simply smaller versions of microwave klystrons. Even if, in principle the dimensions can be scaled according to the frequency increase, the fabrication challenges and the beam characteristic represent a huge obstacle to the realization of a working device when frequency is higher than 50 GHz. This is consequently true for the frequency range around 94 GHz, which is of great interest for communication and radar applications.\n\nThis proposal is aimed to overcome of the above-mentioned obstacle to the design and realization of a 94 GHz klystron by two innovative design solutions. \n\nThe first solution is to operate the cavity at a higher order mode, chosen with similar Ez field distribution on the gap cross-section as the fundamental mode. The design will adopt reentrant cavities with square or rectangular shape, to be compatible with a photolithographic fabrication technique. The higher mode operation permits to design the cavities with dimensions larger (at least 4 -5 times) than in case of fundamental mode operation. This eases the technological effort and makes possible a high quality fabrication by mechanical micromachining or by photolithographic processes. Further, the beam tunnel can be larger than in fundamental mode, to support higher beam current. In order to increase the interaction a number of intermediate buncher cavities, spaced all along the drift tube, will be used to increase the beam current modulation.\n\nA separate approach uses a lower frequency input cavity to modulate the beam current. As the beam travels down the drift tube beam harmonics start to form hence a higher order mode output cavity at an integer harmonic frequency of the input cavity can be exited hence acting as a high power frequency multiplier. As the input can be a readily available high power microwave source we are able to overcome the low gain of the device.\n\n"], "extra_text": ["", "\n\n\n\n"], "status": ["", "Closed"]}
April 11, 2022, 1:47 a.m. Added 35 {"external_links": [11679]}
April 11, 2022, 1:47 a.m. Created 35 [{"model": "core.project", "pk": 2998, "fields": {"owner": null, "is_locked": false, "coped_id": "a81ef61f-e1f7-4a45-86be-1810352b15c4", "title": "", "description": "", "extra_text": "", "status": "", "start": null, "end": null, "raw_data": 18466, "created": "2022-04-11T01:35:27.202Z", "modified": "2022-04-11T01:35:27.202Z", "external_links": []}}]