My 38 GHz Transceiver

This is a Harris Communications Microstar 38GHz Digital Radio tranceiver ODU (out door unit). Unfortunately there isn't a
ham band near this freq. but I suppose it could be doubled to the 76GHz band tho this would be way out of my field of knowledge.
I purchased this brand new (in original packing case) unit off e-bay for just a tiny fraction of its normal sale price mainly to
discover the technology used at such hi frequencies. I was awed at the micro striplines of the 38GHz stages ... truely amazing.
On this page, I would like to tantalise those readers who haven't had the chance to view such technology, with some pics of the unit.
The overall size of the unit is 0.35 metre (~1ft) sqr and .15m (~6") deep. The incorporated flat panel antenna array is fed from
the tranceiver sections by a very short length of waveguide and a very complex divider system (see pics below) that I can't even
begin to understand its operation.

This first pic is an overall view of the inside of the unit with labels on the stages that I can identify.

This pic shows the inside of the TX module. As you can see the striplines are tiny.The multiplier and amplifier stages are
connected to the main PCB by fine gold bonded wires. The main PCB provides the power supply and RF monitoring circuitry.

This next pic is a closeup of the TX mixer, Filter and 1st RF Amplifier stage at 38GHz.
Note the length of the filter section ...10mm less than 1/2 an inch !!

These 2 pics show the divider system that feeds the antenna and a front view of the antenna. The waveguide
bolts to the centre of the system where the RF is divided to feed both halves where it is again divided several
times more. The long black strip to one side of the central feedpoint is a tapered piece of RF absorbing
material presumably used for impedance matching. This whole section is made of copper metalised plastic.

This last pic shows a front view of the antenna one 1/2 of it is covered with a perspex screen.
The array is covered by a plastic radome and bolts directly to the front of the component section of the case.

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Page created 29 Jan 2005