Page devoted to JA1ATI's millimetre wave projects !

Masa has built excellent equipment for 24, 47 and 76 GHz:

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- Masa is active on 47 and 76 GHz using SSB and narrow band FM

- his 47 GHz marker generator (26k) is based on easily available 12.8 MHz TCXO's

- here is the block diagram (6k) of the 47 GHz marker source

- here is a photo of his 4.4 mW Test Source (35k) using an YIG oscillator and diode multiplier

- this is a photo of the 35 cm Cassegrain fed parabolic dish (31k) and downconverter for 76 GHz

- and here is a closer view of the Dual Mode horn feed (27k) in front of the hyperboloid subreflector

- and here is Masa's plot of the 76 GHz Dual Mode (34k) IMU feedhorn

- close in plot of the dual mode horn main lobe for illumination (36k) (measured horn on the left)

- the 35 cm dish is doing an excellent job as you can see from the measured radiation pattern (38k).

- the 76 GHz antenna has a 0.7 degree -3 dB beamwidth (37k)with 45.7 dBi of gain, the first sidelobe is 16 dB down

- multiplying Masa's 9.3 GHz PLL-DRO by two and using a subharmonic mixer, he gets -25 dBm of transmit power !

- stability is good enough for SSB (1.2 GHz IF) using a 100 MHz TCXO and a total multiplication factor of 744 !

- for 47 GHz (66k) Masa is using a 11.455 GHz PLL DRO (6k) with a 114.55 MHz TCXO and a subharmonic diode mixer

- on transmit, the signal is amplified with a Tunnel Diode Amplifier (49k) to a level of 15 mW

- the -3 dB beamwidth of the 47 GHz antenna is 1.2 degrees with 40.1 dBi of gain

performance of the TD Amplifier:

center frequency 47.100GHz
33dB (6k) Gain (small signal)
10mW (-1dB comp) output level (38k) for SSB,AM as linear power amplifier
25mW saturation (24dB gain) output level for NFM,CW
2-stage(6k) tunnel diode amplifier
Room temperature operation (!)
constant voltage bias supply by LM337, -12V/0.69A Total
Masa's link budget calculations (28k) for the TD preamplifier using the amplifier as a preamp (!)
waveguide (WR-22) plumbing

JA1ATI (quasi-optical) lense experiments at 76 GHz:

Masa has also been experimenting with acrylic (quasi- !) optical lenses (6k) for 75 GHz gain :-)
here is a photograph of a typical waveguide flange illuminated 20 dB magnifying glass (65k) for 75 GHz !
and a photo of the 20 dB magnifying glass attached to the 75 GHz transverter (27k)
the measured -3 dB beamwidth (73 k) of the 25 mm dia acrylic lense is 9.5 degrees

Details of Masa's 24 GHz dish feed:

here you may find the mechanical dimensions for Masa's 24 GHz Scalar Horn(100k)
JA1ATI 24 GHz Scalar Horn E & H plane radiation patterns (110k) 10 deg/div and 2.5 dB/div
and a photograph of two beautiful 24 GHz Scalar Horns (27k)

Details of Masa's 47 GHz dish feed:

this is a drawing of the JA1ATI 47 GHz Dual Mode Scalar Horn with mechanical dimensions (47k)
here is a photo of two specimen of the 47 GHz Dual Mode (26k) Feed Horn
the 47 GHz Feed Horn E and H radiation patterns (128k) are measured on Masa's homemade antenna test range ;-)
the Feed Horn also exhibits excellent Return Loss (52k) at around -24 dB (VSWR = 1.13)
some technical information (60k) on the JA1ATI modified TDK antenna

Details of Masa's 76 GHz dish feed:

this is a drawing of the JA1ATI 76 GHz Dual Mode Scalar Horn with mechanical dimensions (69k)
measured H plane radiation pattern (166k) of the 76 GHz horn (E plane is identical)
here you may find a photo of two beautiful 76 GHz Dual Mode Feed Horns (22k) by Masa
Radiation Pattern (175k) of the JA1ATI Feed Horn on a 35 cm TDK Cassegrain dish (+-12 degrees)
and here there is a photo of the prototype 45 cm dish(35k) with a laser pointer for aiding in pointing alignment ;-)

Here are some details of Masa's 47 GHz Bandpass Filter:

This is the technical drawing (49k) with component dimensions
In this photo you can see a ready assembled filter (64k) and also the separate components
Typical test data and material information (2k)
Measured Return Loss (57k) of the ready made and aligned filter
Measured Insertion Loss (60k) of the filter
And this is a photograph of the Band Pass Filter assembled (72k) between Masa's mixer and Tunnel Diode Amplifier

Here is some info on a surplus 13 -> 39 GHz active tripler:

we have recently acquired some very neat 13 -> 39 GHz active triplers; here is a tripler on Masa's workbench (76k)
Masa measured the frequency response of the tripler; results (5k)
He also analyzed the output power as a function of second stage drain voltage: results (5k)
these will make excellent LO sources for doubling 76 GHz mixers ;-)

Some more info on a modified commercial 76 GHz tripler:

here is a photo of Masa's experimental 76 GHz tripler test setup (77k) using a surplus 25 GHz amplifier as the driver
Masa has now achieved a stable output power level of +17 dBm (50 mW !!!) (70k)
here are the current measurement results (9k) of output power vs. input power and calculated conversion loss
combined with his 35 cm Cassegrain fed 45.7 dBi dish antenna, this works out as 2 kW EIRP ;-) ;-) ;-)

Masa's AMSAT OSCAR 40 receiver for 24 GHz:

a new project for Masa is to completely redesign the tracking system (124k) for his K band receiver setup
this tracking system is suitable for moon, sun and satellite tracking
there is a 5mm tele lens+1/4 inch CCD camera for moon tracking with a view angle of approximately 1.8^o
this photo is of Masa's latest K band receiving (48k) setup with a homebrew 75 cm Cassegrain feed
here is the block diagram of JA1ATI's 24 GHz downconverter (146k) for AO-40 K band
This is a photo of Masa's 38 cm dish with radome (43k)
this is a photograph of the noise level of cold sky versus the sun (32k) at 24 GHz
Middle Beacon S+N/N ratio as a function of squint angle (58k) without the radome
A general view of LNA/converter behind the waveguide fed dish (43k)
And an inside view of the frequency reference, converter + LO, LNA and BPF enclosure (45k)
Masa used this setup to successfully pick up SSB, CW and MB signals from AO-40 on Oct. 12. 2001
The dish is a modified TDK TA-383 TVRO dish with 36.9 dBi gain and 2.5 degree half power beamwidth
With three FHX76LP devices the LNA gain is 28 dB and NF measures at 1.77 dB
During this first test the MB readable at S5 (squint about 3 degrees)

Here is an excellent design by Masa for AO-40 K band reception: An LHCP feed for 24 GHz

Masa has designed this LHCP transducer for circular waveguide
Here are the dimensions and structure of the vane (49k)structure
An overall photograph of the vane section (35k)
This polar axial ratio pattern measurement is quite impressive indicating very low ellipticity (6k)
This plot displays the LHCP feed axial ratio (5k) as a function of frequency
Also the matching is quite good as can be seen in this VSWR plot (65k) showing 18 dB of Return Loss
In this photo you can see what the transmit side test bench (31k) looks like for the DUT (circular polarisation)
And in this photo you can see the test bench (35k) of the receiver side (linear polarisation)
And finally a photograph of the linear/LHCP transducer in action on a AO-40 K band receiving antenna (52k)

And Masa's LHCP waveguide feed design using an adjustable delay line with screws for AO-40 K band

Masa experimented with this simple LHCP transducer for circular waveguide
Here are the dimensions and structure of the screw delay line (11k) structure
An overall photograph of the delay section (14k)
This polar axial ratio pattern measurement indicates low ellipticity (22k) after alignment
This plot displays the aligned LHCP feed axial ratio (30k) as a function of frequency

Here you may find the JA1ATI "IMU" dual mode design for 24 GHz:

This is the mechanical drawing of Masa's 24 GHz dual mode feedhorn (69k)
The E and H plane radiation patterns reveal nice shape and the 95/96 degree radiation pattern (120k)
And a photograph of two feeds (28k), one complete and the other disassembled

Masa and friends have been very busy testing their millimetre wave band equipment:

Here is a beautiful photo (95k) of the setup during a 151 km test of JA1ATI & JA1ELV
The above location is on Mount Tukuba, Maidenhead: (WGS-84) QM06BF
The DX was the Mount Fuji view point car park at Maidenhead (WGS-84) PM95JI, elevation 2000 - 2500 m ASL
Line of sight visibility from the Fuji-san location is about 220 km, further distances are difficult in Japan
This QSO attempt (October 7th, 2001) was foiled by bad weather
In November this path was established on 75 GHz using NBFM by another group
In this photo you can see a 20 dB JA1ATI antenna horn (150k) for 24 GHz
Using this horn, raports are 59+ over th 151 km path on 24 GHz in suboptimal weather conditions

Here is some data on JA1ATI's experimental tapered helical waveguide launcher for 24 GHz:

Mechanical layout and dimensions (55k)of the waveguide helix
The VSWR (42k) is less than 1.3 (return loss ~19 dB)
This is a plot of the feed ellipticity (76k) at 24048 MHz
Here is a plot of axial ratio (64k) as a function of frequency
And finally a photograph of the tapered LHCP helix (24k) for generating RHCP with a prime focus dish

Masa's 24 GHz kitchenware antenna !

the basis for this antenna is a regular sieve (55k) that happens to have a parabolic shape to it's surface
Using the old elegant "penny feed" concept (42k), this reflector can be fed very nicely
A photo of the completed 24 GHz antenna (76k) speaks for itself :-)

JA1ATI LASER optical communications experiments

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