What do you mean by simple receivers ? What are you trying to receive,
with what stability and sensitivity ? Amateurs have traditionally used
crystal-controlled downconverters in front of lower frequency
receivers, but this is generally suited only for receiving small
segments of spectrum and doesn't usually have a very small parts count.
The local oscillator usually involves several multiplier stages and
tunable filters. The performance can be very good though.

For example there are lots of technical articles at

http://dpmc.unige.ch/dubus/index.html

The 1N5711 schottky diode works well in the lower microwave range and
is quite widely available and cheap.

Steve VE3SMA

wrote in news:1145727069.586990.95580
@j33g2000cwa.googlegroups.com:

What do you mean by simple receivers ? What are you trying to receive,
with what stability and sensitivity ? Amateurs have traditionally used
crystal-controlled downconverters in front of lower frequency
receivers, but this is generally suited only for receiving small
segments of spectrum and doesn't usually have a very small parts count.
The local oscillator usually involves several multiplier stages and
tunable filters. The performance can be very good though.


Something that can be built with 1 chip just to experiment for now.
From what I read, regular fiberglass boards don't work well above 1 GHz.
Where do you get teflon boards?

JJ

"JJ" wrote in message
...
wrote in news:1145727069.586990.95580
From what I read, regular fiberglass boards don't work well above 1 GHz.

That's a bit of an overgeneralization. We routinely use "generic" FR-4 to
3GHz, and you'll find that many wireless routers at 2.4GHz do as well. As
long as the paths are relatively short and you're just using the board to get
a signal from point A to point B, it works pretty well.

The folks who suggest you use Teflon or other high-quality board materials are
probably thinking of building distributed circuits on it -- stuff like
filters, where the board's loss (its Q) significantly impact how good your
filter's response is. (Building something like a bandpass WiFi filter --
~25MHz wide at ~2.45GHz -- on FR-4 using coupled lines is probably not such a
hot idea -- this would be a good test case to simulate.)

Where do you get teflon boards?

All the decent-sized board houses (e.g., Advanced Circuits, DDI, etc.) have
low-loss board materials available. Nelco (http://www.parknelco.com/) and
Rogers (http://www.rogers-corp.com/acm/index.htm) are two of the big players
here. We have many boards done in Nelco 4000-13, which is a "mid-loss"
material... only somewhat better than FR-4 when it comes to absolute loss, but
considerably better when it comes to the specs not drifting over process,
temperature, etc., all at a relatively small pricing premium.

If you can afford it, by all means, get low-loss boards. However, in many
cases in the low-GHz area you end up with more loss from items such as coax
cable, connectors, impedances mismatches, etc. than the PCB material itself.

---Joel Kolstad