Microwave diode?

  Have simple detector circuit that specifies 1N21B diode. That diode is
20-plus years old and obsolete. Looking for current equivalent, possibly (but
not necessarily) smt.

Are these useable in place of a 1N21B for 2.4 GHz detection?:

<http://tinyurl.com/6g62bu>

<http://tinyurl.com/62fqnv>

Suggestions welcome.

Thanks,
--
DaveC
me@bogusdomain.net
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Those look good. Skyworks has some really nice low-barrier Schottky
diodes. And they have a fabulous sample kit of schottkies and
varactors, lots of parts.

Go for "low barrier" parts for unbiased low-level detection.

The best detectors are probably germanium back diodes, but expensive.

Several semi companies now make active detectors... LTC, ADI.

John

 

John Larkin wrote:


There was a thread about this a few months back in s.e.d IIRC.

Graham

Alt group trimmed

 

John Larkin wrote:


Any idea how well 0.35pF compares with a point contact type ? Googling 1N23B
brings up plenty of data including that for the 1N21B but I've yet to see any
capacitance figures.

"These point contact "cat's whisker" devices, are still made occasionally because
of their very small capacitance. As it was discovered early on, they are highly
useful in high frequency electronics."

http://www.oddmix.com/tech/cr_from_crysdets_todiodes.html

Graham

 Eeyore wrote:

because

Almost as important as the capacitance, which is
covered by the frequency range anyway, ist the
case. It should suit the application, meaning the
geometry of the mounting. The manufacturers divide
into mixer diodes and detector diodes. The detector
diodes are specified in terms of mV/uW together
with a loading. The loading is connected to the
video bandwidth. The higher the bandwidth the
lower the load. I'm not too familiar with 2.4GHz,
but assume few kOhms would be usual. There are
different sort of bias to achieve a high
sensitivity. RF of the same frequency, but adjustable
phase, DC, none. This usually is given by the setup.

I wasn't yet able to figure out what happens
when a zerobias detector is suddenly biased, or
whether a DC bias detector can be RF  biased.

Rene