| Records |
| Author |
Tol, J. van; Brunel, L.-C.; Wylde, R. J. |
| Title |
A quasioptical transient electron spin resonance spectrometer operating at 120 and 240 GHz |
Type |
Journal Article |
| Year |
2005 |
Publication |
Rev. Sci. Instrum. |
Abbreviated Journal |
Rev. Sci. Instrum. |
| Volume |
76 |
Issue |
7 |
Pages |
074101 (1 to 8) |
| Keywords |
Schottky, noise temperature |
| Abstract |
A new multifrequency quasioptical electron paramagnetic resonance (EPR) spectrometer is described. The superheterodyne design with Schottky diode mixer/detectors enables fast detection with subnanosecond time resolution. Optical access makes it suitable for transient EPR (TR-EPR) at 120 and 240 GHz. These high frequencies allow for an accurate determination of small g-tensor anisotropies as are encountered in excited triplet states of organic molecules like porphyrins and fullerenes. The measured concentration sensitivity for continuous-wave (cw) EPR at 240 GHz and at room temperature without cavity is 1013 spins/cm3 (15 nM) for a 1 mT linewidth and a 1 Hz bandwidth. With a Fabry-Perot cavity and a sample volume of 30 nl, the sensitivity at 240 GHz corresponds to [approximate]3×109 spins for a 1 mT linewidth. The spectrometer's performance is illustrated with applications of transient EPR of excited triplet states of organic molecules, as well as cw EPR of nitroxide reference systems and a thin film of a colossal magnetoresistance material. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication  |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
Actually, noise spectral density is given (3e-19 W/Hz) |
Approved |
no |
| Call Number |
|
Serial |
588 |
| Permanent link to this record |
| |
|
| |
| Author |
Archer, J. W. |
| Title |
Multiple mixer, cryogenic receiver for 200-350 GHz |
Type |
Journal Article |
| Year |
1983 |
Publication |
Rev. Sci. Instrum. |
Abbreviated Journal |
Rev. Sci. Instrum. |
| Volume |
54 |
Issue |
10 |
Pages |
1371-1376 |
| Keywords |
Schottky, mixer, noise temperature |
| Abstract |
This paper describes a new 200–350-GHz dual polarization heterodyne radiometer receiver for radio astronomy applications. The receiver incorporates four pairs of cryogenically cooled Schottky-barrier diode single-ended mixers, each pair covering a 30–40-GHz subband of the full operating band. Each mixer, with its IF amplifier, is mounted in an individual cryogenic subdewar comprising a separate vcuum chamber and a cold stage, which may be readily thermally connected to or disconnected from the main refrigerator by a novel mechanical heat switch. A dual polarization LO diplexer is mounted on a rotary table above the subdewars. For band selection, the two diplexer rf output ports may be positioned over any of the four pairs of subdewars. The SSB receiver noise temperatues achieved are less than 500 K between 200 and 240 GHz, less than 800 K between 245 and 275 GHz and 1500 K at 345 GHz. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
|
Serial |
589 |
| Permanent link to this record |
| |
|
| |
| Author |
Hirata, A.; Harada, M.; Nagatsuma, T. |
| Title |
120-GHz wireless link using photonic techniques for generation, modulation, and emission of millimeter-wave signals |
Type |
Journal Article |
| Year |
2003 |
Publication |
J. of Lightwave Technology |
Abbreviated Journal |
|
| Volume |
21 |
Issue |
10 |
Pages |
2145-2153 |
| Keywords |
subterahartz terahertz THz communications |
| Abstract |
We present a wireless link system that uses millimeter-wave (MMW) photonic techniques. The photonic transmitter in the wireless link consists of an optical 120-GHz MMW generator, an optical modulator, and a high-power photonic MMW emitter. A uni-traveling carrier photodiode (UTC-PD) was used as the photonic emitter in order to eliminate electronic MMW amplifiers. We evaluated the dependence of UTC-PD output power on its transit-time limited bandwidth and its CR-time constant limited bandwidth, and employed a UTC-PD with the highest output power for the photonic emitter. As for the MMW generation, we developed a 120-GHz optical MMW generator that generates a pulse train and one that generates a sinusoidal signal. The UTC-PD output power generated by a narrow pulse train was higher than that generated by sinusoidal signals under the same average optical power condition, which contributes to reducing the photocurrent of the photonic emitter. We have experimentally demonstrated that the photonic transmitter can transmit data at up to 3.0 Gb/s. The wireless link using the photonic transmitter can be applied to optical gigabit Ethernet signals. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
|
Serial |
592 |
| Permanent link to this record |
| |
|
| |
| Author |
Nagatsuma, T.; Hirata, A.; Sato, Y.; Yamaguchi, R.; Takahashi, H.; Kosugi, T.; Tokumitsu, M.; Sugahara, H.; Furuta, T.; Ito, H. |
| Title |
Sub-Terahertz Wireless Communications Technologies |
Type |
Conference Article |
| Year |
2005 |
Publication |
Proc. 18th International Conference on Applied Electromagnetics and Communications (ICECom 2005) |
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
1-4 |
| Keywords |
subterahartz terahertz THz communications |
| Abstract |
This paper presents a 10-Gb/s wireless link system that uses a 120-GHz-band sub-terahertz electro-magnetic waves. In the transmitter, photonic techniques are used for generation, modulation, and emission of the sub-THz signals, while the receiver is composed of all-electronic devices using InP-HEMTs. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
|
Serial |
593 |
| Permanent link to this record |
| |
|
| |
| Author |
Koch, Martin |
| Title |
Terahertz communications: a 2020 vision |
Type |
Book Chapter |
| Year |
2007 |
Publication |
NATO Security through Science Series |
Abbreviated Journal |
|
| Volume |
2007 |
Issue |
|
Pages |
325-338 |
| Keywords |
terahertz THz communications |
| Abstract |
We discuss basic considerations for potential short-range THz communication systems which may replace or supplement present WLAN systems in 10–15 years from now. On the basis of a few fundamental estimations we show that such a system will need a line-of-sight connection between receiver and emitter. To circumvent the blocking of the direct line-of-sight connection indoor THz communication systems will also have to rely on non-line-of-sight paths which involve reflections off the walls. The reflectivity of the walls can be enhanced by dielectric mirrors. This new scheme makes steerable high-gain antennas a necessity. Hence, a wireless THz communication system can not be a simple extension of the existing technology of today's local area networks. Instead it involves completely new concepts and ideas that have not yet been worked upon. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
|
Serial |
594 |
| Permanent link to this record |
