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CHM Series - Sub-millimetre Wave Quasi-Optical Harmonic Mixers |
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Thursday, 24 May 2007 |
Features
- Standard Waveguide Input for LO
- Backshort Tuning on LO Input
- Corner Cube Wire Antenna for RF
- Broadband Low Loss RF Operation
- GaAs Schottky Barrier Diode for Optimum Performance
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Applications
- Frequency Metrology
- Gaseous Spectroscopy
- Tunable FIR Sources
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Description
There are many applications where submillimeter wavelength mixers are required and where the signal/noise ratio or the conversion loss requirements are such that expensive fundamental mixers/LO sources are not required.
Farran Technology has a range of harmonic mixers specifically designed for submillimeter wavelength applications. The photograph shows a harmonic mixer designed for an LO frequency of 100 GHz and an RF frequency of 1500 GHz. The input LO power is via a waveguide built into the ground plane of the corner cube structure while RF input is via the corner cube antenna.
The diode chip is contacted by the whisker antenna and is located in the waveguide so that a tunable backshort can be used to independently couple the 100 GHz radiation into the mixer diode. This structure combines waveguide and optical techniques in a compact reliable structure which makes optimum use of both technologies.
In the submillimeter region where LO power is generally scarce and expensive, this harmonic mixer structure is an excellent low-cost solution for extending the frequency capabilities of your laboratory, with obvious benefits in frequency metrology, plasma diagnostics, etc. |
Specifications
Model
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RF Frequency
(GHz)
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Waveguide / Flange
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LO Frequency
(GHz)
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LO Power
(mW)
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Harmonic |
Signal / Noise
(dB typ)
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Conversion Loss
(dB)
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NEP
(W / Hz)
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CHM-1 |
300-600 |
WR10 |
75-110 |
5 |
5 |
53 |
35 |
5 x 10-14
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WR12 |
60-90 |
6 |
50 |
40 |
10-13
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WR15 |
50-75 |
7 |
47 |
45 |
2 x 10-13
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CHM-2 |
600-800 |
WR10 |
75-110 |
10 |
8 |
47 |
45 |
2 x 10-13
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WR12 |
60-90 |
9 |
43 |
50 |
5 x 10-13
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CHM-3 |
800-1000 |
WR10 |
75-110 |
15 |
10 |
43 |
50 |
5 x 10-13
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WR12 |
60-90 |
12 |
40 |
55 |
10-12 |
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CHM-4 |
1000-2000 |
call |
75-110 |
call |
call |
call |
call |
call |
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CHM-5 |
2000-3000 |
call |
75-110 |
call |
call |
call |
call |
call |
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Notes
- Assuming a 1 mW RF available and S/N measured into 100kHz bandwidth.
- Pump Coupling – we recommend the use of flexible waveguide into the pump port. This will give positional flexibility which will be advantageous in setting up the optical alignment correctly.
- Optical Coupling – It is essential that correct coupling is effected to the RF port. Suitable lenses or mirrors are available from FTL. The input beam should have 10dB full beam width of 24 degrees. This corresponds to F/D № of 4.3 to the 3dB points. The beam waist should be located at the whisker tip.
- These detectors have been constructed to be mechanically robust and to provide trouble-free operation if they are handled with reasonable care. However, in common with all whisker-contacted structures they can be accidentally damaged. Farran Technology provides a fast turnaround time on recontacting or whisker replacement for units which are returned to the factory.
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Typical Outline
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Unit 1, Airport East Business Park, Farmers Cross, Cork, Ireland
Phone: +353 21 4849170
FAX: +353 21 4849192
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