I am building a family of low cost shield boards that will enable makers and hobbyists to dip their toes into the world of microwave circuits. With Arduino, Teensy and R Pi compatible shields, makers will finally be able to experiment with stuff they don't see in everyday electronics: frequency synthesizers, spectrum analyzers, RSSI detectors, IQ modulators, network analyzers and many more. High frequency circuits always seemed a bit like a black magic - I hope this project will encourage many to prove it isn't.
I will start with a simple frequency synthesizer, that is based on my previous project, Microwave transmitter. Synthesizer, based on Maxim Integrated chip MAX2871, will synthesize frequency in range 23.5 MHz - 6000 MHz. Neat, eh?
There were some issues with the tested version 1.0. It seems that desire to go cheap backslashed at me. I hoped I'll be able to go with 2-layered board with this oscillator. But unfortunatelly, it didn't work as planned. There was long return trace due to the ground plane not being even on any of two layers.
Microwavino v2.0 consists of 4 layers what should eliminate these issues and make everything work as in my project microwave transmitter.
Boards from OSH Park have finally arrived, as well as stencil from OSH Stencil and components from RS components. This meant only one thing: SMDs, assemble!
It took me 5 hours to manually assemble and reflow these two Microwavinos.
The results were not really fascinating, some rework had to be done. It was mostly 0402 components that were soldered to the ground plane on one side. Surprisingly, those 44 pin QFNs got soldered flawlessly.
While waiting for PCBs to arrive, I've designed another board in Microwavino family - coupler with RSSI detectors. The idea behind is to have input and output coupled to the RSSI detectors to measure transmitted and reflected power. Together with Microwavino Synthesizer board, this can be used to make a scalar network analyzer.
Today I finished project design and sent everything to fabrication. I ordered PCBs from OSH Park (5$) and kepton stencils from OSH Stencils (8.45$ with shipping). I expect to get everything ready for assembly in next 20 days. Till then, over and out!
Well, it's not its purpose, but I tested function called frequency sweep on it and it blocked FM spectrum in amount of time short enough to be called "at once". :)
This is awesome! Please put my name down for a set of boards for a DIY VNA. Thanks!