I am currently researching methods to create a frequency doubler, so far I concluded to use a Schottky diode in a rectifier bridge configuration to create the Fx2 harmonics. Can you provide guidance on a transformer that is best for this purpose, and also the best diode to use?
5 MHz to 10 MHz, unity power gain
For frequencies that low, the balun options would be the BALH-0003SMG or BAL-0003SMG. These are also available as connectorized units, although I don’t think that would be compatible with your packaging requirements. These baluns will provide the best possible suppression of the fundamental, third, and other odd harmonics. You will need to add an amplifier to counteract the loss in the baluns and diode quad.
Another option is to use a flux coupled balun from another company, if your primary concern is with loss and not harmonic suppression.