A simple signal generator


This is a simple frequency marker that uses a simple 1N23 microwave diode and a 48/50 Mhz computer oscillator to generate harmonics up to 10 Ghz. You could use any type of oscillator from 48 to 51 MHz, but I suggest TTL computer oscillators, because square waves are more rich in harmonics. The sgnal is amplified by a monolithic amplifer, and applied to the 1N23, that, as a non linear device, distort it generating harmonics in the microwave region. The diode have to be inserted in an adequate cavity: you could build it from a piece of WG16, closing one end and placing the diode a quarter of wave from the closed end, centered (very, very difficult....) or use a microwave module (for example one with a burned Gunn...).

About the MMIC, you could use any device that works on the region of 6/8 GHz (ERA1/2/3/5 o MGA64135/MGA86576 etc...). R is the current limitation resistor, it depends on the device you use; you could calculate its value using the tables on the datasheet (you find them on the net). RFC is a VK200 or similar. If the signal s not strong enough, you could use more amplifiers in cascade.

on't forget to keep connections the more short possible and to insert the generator in a metallic box, using feedthroug to keep biass voltage.

Good work!

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