Xinping Zeng Zhizhang Chen Frequency Multiplication and QPSK Modulation with Subharmonic Injection-Locked Active Antenna. 329-332 2004 conf/cnsr/2004 CNSR http://doi.ieeecomputersociety.org/10.1109/DNSR.2004.1344746 db/conf/cnsr/cnsr2004.html#ZengC04