SSB modulator for low cost data transmission based on reflection of 10GHz signal.

SSB modulator for low cost data transmission based on reflection of 10GHz&up signal.

Hello! I want to discuss one interesting topic and ask how to implement ideas.

Assume we have
1. Master device, that must receive microwave signal, for example at 10GHz or higher
2. Slave devices, that transmit microwave signal, and must be very cost effective

Here is the idea:
Master device continuously transmit LO signal through omni-directional antena.
Slave device contain SSB quadrature modulator, and uses received Master device microwave signal as LO. After modulation, signal received by Master device and decoded.

This is very interesting solution, as only master device need an oscillator, and it can be almost any type. Slave devices only need 4 Schottky diodes, microstrip board and circulator (that i want get rid of). In such configuration we can do high speed transmission from Slave devices that are in LO radiation range of Master device. Each Slave data burst contains checksum, and Master device decodes and process only successive frames. It maybe remind you RFID tag, but here the requirement is that Slave device transmit big amount of data (spectrums, images, etc.) in a short period of time, and also Slave device have AC220 source or battery powered (burst transmissions).

I checked idea a little on practice and it seems promising. The only not so cost effective part is circulator in slave device. As slave device contains microstrip IQ modulator, it's LO intput and RF output must be isolated. LO input connected to RX antenna, and RF output to TX antenna.

As i know, it is possible to build reflection type SSB modulator, where only one antenna is used. I've been told, that it can be done by re-configuring quadrature hybrid in some way i do not understand. Quadrature hybrid mixer contains LO, RF and IQ port. IQ port is used for modulation. LO and RF ports currently connected to RX and TX antenna. How i can reconfigure hybrid mixer to get rid of LO port, and use only RF port to simultaneously receive LO and transmit modulated RF signal?

Thanks!

To transmit data no SSB modulator is needed. An ordinary diode detector connected to an antenna can modulate its reflection by alternating diode bias.
Such devices are named "modulated scatterers" and you can find more in a book by Bolomey and Gardiol, Engineering Applications of Modulated Scatterer Techniques.

I see, that would be easier. Also found quadrature modulated scatterer in google, thanks right naming.