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Using ADL5391 to cancel antenna-to-antenna coupling in phased-array radar

Question asked by M.K.Edwards on Jun 21, 2011
Latest reply on Jul 1, 2011 by M.K.Edwards

I'm sketching out a phased-array radar design (RFID reader, actually, but it's basically the same thing) that needs accurate cancellation of Tx->Rx feedthrough (largely due to coupling among the antennae).  The Tx signal (915 MHz band) needs to be phase-shifted, scaled, and added to the Rx signal.  Judging from the ADL5391 datasheet, it would be suitable for this use, given a voltage-controlled phase shifter at one input and the appropriate in-system measurement and control paths.


There are various design challenges here, some of them application-specific.  But the first is to get a handle on this new multiplier architecture, and in particular on its impedance matching requirements, which could complicate the implementation of the varactor-based phase shifter.  Is there an ADL5391 application note, or other reference design, that would help?


Thanks in advance,

- Michael