#QUCS LOW PASS FILTER TUTORIAL HOW TO#
#QUCS LOW PASS FILTER TUTORIAL SOFTWARE#
#QUCS LOW PASS FILTER TUTORIAL SERIES#
#QUCS LOW PASS FILTER TUTORIAL SIMULATOR#

But there are limits on how narrow or how wide you want to go. Similarly if you want an open circuit quarter wave line to look like a short, the bandwidth will increase for a lower impedance wider line. For example, if you want a short circuit quarter wave line to look like an open circuit, the bandwidth will increase for a higher impedance narrower line. The width of the line depends what you are using it for. And I almost forgot RFSIM99, but this won't help, that one can't do diodes/non-linear elements.

#QUCS LOW PASS FILTER TUTORIAL SOFTWARE#

Currently, the only RF software tools available I have are a copy of unusable Sonnet Lite and a Ansoft Designer SV, which is a free restricted (IDK how) student version I have scored somewhere on a web.

#QUCS LOW PASS FILTER TUTORIAL SIMULATOR#

Now the question is, what circuit simulator to use for the step 2, that I could fill in the model of the diode. 5) Convert the electrical schematic to a microstrip design, simulate and optimize it (this might be the hardest part) 6) Call it a day. 4) Preferably match also LO that it doesn't make unnecessary termination for RF and mainly the IF frequency (conversion loss increased otherwise). 3) match the RF, IF ports, so that IF port is open at RF frequency and RF is open at IF frequency. 2) Simulate the diode mixer, just two ports with the required shunt (IF return) and open (LO termination) stubs to obtain the impedance at LO port at LO frequency and to obtain impedance at port 2 (RF, IF) at the IF and RF frequencies respectively. I think my HSMS-2822 with its 6ohm and 0.7pF is good enough for 3.4GHz. higher than desired frequency of operation).

#QUCS LOW PASS FILTER TUTORIAL SERIES#

Series resistance R s and chip capacitance C j0 are of the main concern, 1/2*pi*R s*C j0 should be high enough (i.e. Is there anything free (or that could be made free) suitable for this? To sum up for others interested in such MW mixers, what I understand the design process should be as following: 1) Choose suitable mixing diode. What I need is at least a circuit simulator capable of simulating non linear devices, like diodes. After reading a bit, I can kind of understand the design principles of the mixers. The other possibility if you don't want to simulate is just set up the basic mixer on the bench and tune it by hand. But just using the simulation software is the way to go. His books are quite academic and not too practically oriented.

Steve Maas has written a lot of books about mixer design: In those, he outlines a method similar to harmonic balance that can be used to calculate impedances. Many broadband mixers aren't actually matched at all and still give relatively good performance. This page gives a list of app notes, but the links don't seem to work: Here is one on harmonic mixers (obtained by googling), seems like a typical academic paper: You might want to look at what Marki Microwave has to say about simulation: I have heard the free simulator QUCs has harmonic balance, but I have never used it: Matching is often not that important. Even if you don't have those simulators, it may be useful to look at their app notes. My experience is this gives really good results, since the only nonlinear elements are the diodes which are very easy to model. You need a harmonic balance simulator like in Keysight ADS or NI AWR Microwave office. The typical way to design a mixer is to use a simulator. I know that there are plenty of ready made 50ohm matched passive and even active mixers these days, that are very easy to implement into a design. Please understand this is more like an experiment, mainly out of my curiosity and to improve some knowledge. The proper mixer diode pair I have available is HSMS-2822 (datasheet), which I think should be sufficient.

#QUCS LOW PASS FILTER TUTORIAL HOW TO#

What I am after is how to guesstimate: 1) The impedance of the transmission lines to be used around the diodes 2) How to match these so the mixer will become as close to 50ohm as possible on all three ports. Those lambda/4 or lambda/2 stubs are the only things straightforward I understand there. Now that I have access to some proper test gear, I would like to give it a second chance. I have already had a go with this about two years ago, copied a design from some 'schematic collection book', but the performance was really crap, totally unusable. Supposed I want to try designing a mixer for a 9cm band (3400MHz) - which is actually what I want to try. Especially, I am interested in how these things are supposed to be designed to work properly at microwave frequencies.

Here is what is going on: I would like to ask, if you have any tips for literature or have a first hand experience building these. I am more interested in the microwave band use of this mixer, as at HF it is quite easier to make it work as it should. Hi! I have seen quite a lot that subharmonic diode mixers (also often called 'russian mixesr' or the 'Polyakov RA3AAE mixers') are quite popular in many amateur radio construction, from HF up to microwave bands.

Qucs low pass filter tutorial