Basic Tripler Circuit 1

[krytar]

I've designed frequency doubler (.005-3GHz & 1-11GHZ) using bridge quad diode using core and wire for the lower freq & microstrip for the higher frequency band.

I need help on designing low frequency tripler with input from 50-150MHz & 240 -375MHz, +10dBm power input & +15Vdc.

I'd like to know the basic design/circuit?


Thanks,
Krytar

 

[biff44]

http://www.wenzel.com/documents/2diomult.html

http://www.wenzel.com/documents/hints.htm

 

[biff44]

Shotkky diode multipliers are pretty lossy. If you want low loss, or even gain, consider a varactor diode, or transistor multiplier.

 

[krytar]

Thanks, Biff44

I checked on Wenzel's papers, and found one of his article on RF magazine is very interesting. From a mixer doubler topology, where a bridge quad is used, he rotates the quad to move the common cathode (from the output) to the next arm connection. Voila! he transforms an even-mode to an odd-mode mixer multiplier.

I'm using Wenzel's topology to turn my frequency doubler into a tripler. Will post the result if it works at all.

Does anyone know if Charles Wenzel is related to Bob Wenzel (a RF/Microwave filter guru)? I worked with Bob on some multiplexers sometimes ago.

Thanks,
Krytar

 

[GOTWW]

I remember being in reviews about HP triplers w/ monolithic schottky diode arrays, they were very concerned about some "idling current", I was lost. Can somebody now fill me in what is this idling-circulating current is why it was apparently so importent?

 

[biff44]

Idler current is the general term for current flowing in the "multiplier" that is not at either the input or desired output frequency. Generally, one wants to reactively terminate the major idler frequencies, so that output power is not squandered there. Don't confuse the various types of multipliers. I would group them in four groups: 1) passive rectifying multipliers, like shottky diode ones, that are either push-push for even order harmonics, or antiparallel (clip tops and bottoms of sine waves) for odd harmonics. These multiply simply based on the fact that the rectified or clipped output waveform has a fourier content at the frequency of interest. Typically very lossy, at least 10 dB. Terminating the unwanted frequency idler currents in these multipliers is probably not worth it, because the lossy diodes do not allow you to recover that idler energy into the desired frequency output. 2) active device like bipolar or transistor, who because of the added DC power can operate with less conversion loss. In these multipliers, you can gain some efficiency by reactively terminating the unwanted frequency currents (idler currents). A time-domain way of thinking about it is if you are trying to get a X3 output, you can "short out" any content at X2 and X4, leaving the remaining horsepower of the active device to only produce the desired X3. 3) reactive multipliers, like varactor diodes, which are very efficient but demand that you reactively terminate the unwanted frequencies. I have made passive doublers that had 2 dB conversion loss. The idea, valid because the varactor is low loss, is one of conservation of energy. If you put in energy at one frequency, but only allow it to resistively dissipate at the desired output frequency, the conversion will be very efficient. Penfield wrote a good book on the effect a coon's age ago. 4) Impulse type devices, like step recovery comb generators or digital gates, that generate a wide number of odd, or even, or sometimes both harmonics at very high conversion loss by forming a spike out of a sinewave input. Here idler currents are of no factor. Since the spike width is very narrow in time, it contains very little energy; and since there are many frequency "teeth" sharing that energy, the total conversion loss is very high (25 dB or so).

 

[GOTWW]

Thanks Biff, It has been a while, but sure thought the arrays were schottky diode arrays, but they could have been arrays of varactor diodes I guess. That program died and ugly death as I recall. Now not to be a pain, but is Idler a reference to a person, or an abstract representation of the familier idler pully?

 

[biff44]

A reference to the old Allman Brothers record "Idler Wild South"?

 

[krytar]

It works!

My tripler works! I used Wenzel method using a Metellic bridge quad diodes to convert sinewave to squarewave.

Inject 300MHz signal to input port, I've got 900MHz signal output @20dB loss with 56dB fundamental suppression, second harmonic is way down at noise floor.

The conversion loss is high (will be taken care off by adding a cheap amp at the output). Bandwith is a bit narrow: 280-340MHz (for 840-1020 MHz output).

Thanks everyone
Krytar