Class D and class E,F amplifiers.
Alex- correction for previous post about class D: “. . .PAE (Power Added Efficiency) can be around 100%. Some matching for impedance should be done, but that is a minor question.. . .”
Last statement is not true. According: http://liu.diva-portal.org/smash/record.jsf?pid=diva2:240432 matching impedance eats 60% of efficiency. Suggestion in article to use Class E
with proper impedance matching in topology. But for class E and Bluetooth this also stated in http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4770499&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D4770499 that with 22.7 dBm (186mW) it is 36%PAE and for 26.4 dBm (437 mW) PAE = 30%. Needs to ask – does they actually made such device or it is just theoretical calculations on simulators.
Tubes/wave. To make experiments needs to have ability to get high vacuum inexpensive way – glass can be printed, everything can be printed and packed into glass. It is funny – to get the vacuum (free on the orbit) needs to have a vacuum (expensive on earth) – Isn’t it?
Antenna will arrive tomorrow. It will be possible to make measurements with 0dBm to compare helical and modified helical designs. I discussed today with Boris crazy idea about make modified antenna with active antenna’s sections. He looked at me like professor of physics looks at perpetuum mobile’s inventor. Active antenna skipped.
And you have no idea what I bought looking for wave tubes! PDP-11 processor! – Old! golden pins shining brightly! (at least on picture). It will be embedded into Cube-sat – may be we can connect a power pin to a ground!