Simplest way for testing 42GHz oscillator

[Ejaz484]

Hi,

I have got 42GHz oscillator and my job is to test it. Can anyone suggest the simplest way and also accurate way of testing it either with VNA or Spectrum analyzer.

It would be helpful if any one suggest the pdf or any other information where i can found the relevant information regarding this testing

 

[jiripolivka]

Hi,

I have got 42GHz oscillator and my job is to test it. Can anyone suggest the simplest way and also accurate way of testing it either with VNA or Spectrum analyzer.

It would be helpful if any one suggest the pdf or any other information where i can found the relevant information regarding this testing

There are basic specifications that should be known. For instance, you MUST know the DC power supply voltage and use it, and you MUST know the DC current to select a regulated power supply. Do not use a switching power supply as it generates bad spurs.

Then your oscillator comes with a waveguide (possibly a coaxial) output. You must find a good power meter matching the waveguide or coax output and calibrated, also capable to measure the expected output power.

To test output spectrum purity you need a good attenuator to reduce oscillator power to use a spectrum analyzer. Many spectrum analyzers (except new expensive ones) cannot directly accept 42 GHz, so you must find a compatible harmonic mixer and learn to work with it. Find white papers by Agilent where details are explained.

Depending on application, you may need to see frequency pulling by a variable load, or use an isolator to prevent it. Many oscillators, Gunn as well as DROs generate harmonics, so often one needs to use such oscillator with a low-pass filter to get a clean output.

Do not forget to use a heat sink, get ready to monitor oscillator body temperature. Many oscillators vary frequency by temperature, so you should take a record of such variation vers. temperature.