This paper describes a millimeter-wave broadband monolithic even harmonic image rejection mixer with a ring connected anti-parallel diode pair. This mixer employs an even harmonic mixer with a ring connected anti-parallel diode pair to reduce the LO leakage. Also it employs the balanced type mixer with the Marchand balun to broaden the frequency range. Furthermore, the configuration of the image rejection mixer can suppress the image components.The chip size of the developed millimeterwave broadband monolithic mixer is 1.2 mm x 2.9 mm on a GaAs substrate. Conversion loss is less than 15.9 dB and image rejection ratio is more than 12.5 dB from 24 to 44 GHz. Broadband characteristics can be achieved by the proposed configuration.

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Absrtact: This paper presents a new scheme of direct conversion phase shift keying (PSK) receivers applicable to time division multiple access (TDMA) land mobile communication systems. In the scheme, a matched filter in each I and Q channel is divided into two parts in front and at the back of a baseband amplifier to reduce baseband noise power and improve sensitivity. A rational design method to divide the filter is proposed; the filter cell that has narrowest equivalent noise bandwidth in the filter is chosen as the back part, while the remainder constitutes the front part. Moreover, memories are employed to eliminate DC offset in baseband signals. Experimental results show that, when applied to Personal Handy Phone System (PHS), a receiver employing the scheme achieves sensitivity comparable to that of a super-heterodyne receiver in continuous and burst reception.