Recent work on receivers for the 60GHz band has considered various frequency plans to ease the design of the building blocks, particularly the local oscillator (LO) and the frequency dividers [1][2][3]. A natural choice of the LO frequency in a heterodyne system is half of the input frequency as it places the image in the vicinity of zero while greatly simplifying the design and distribution of the LO and divider signals [4]. Unfortunately, a simple heterodyne chain consisting of a single RF

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... er and quadrature IF mixers suffers from an additional image introduced by the third harmonic of the LO in the RF mixing operation, which flips the signal spectrum horizontally and superimposes it on the original downconverted spectrum. Since the third harmonic of the LO is only 9.5dB lower, this corruption proves serious in modulation schemes having asymmetric spectra, e.g., FM, QPSK, and QAM.