Hiroshi Ikematsu

A millimeter-wave broadband monolithic even harmonic image rejection mixer

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 millimeter-wave broadband monolithic mixer is 1.2 mm/spl times/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.

A monolithic even harmonic quadrature mixer using a balance type 90 degree phase shifter for direct conversion receivers

This paper proposes a novel circuit configuration of an even harmonic quadrature mixer (EHQMIX) for direct conversion receivers. In this EHQMIX, a 90 degree phase shifter consists of balance type high pass and low pass filters, and it does not require any circuits connecting to the ground plane. So this configuration is suitable for low cost monolithic IC without any via-holes, because amplitude and phase imbalance caused by inductance included in wires and leads of a package for circuits to the ground plane can be reduced. A developed L-band MMIC achieves good quadrature detecting characteristics.This paper proposes a novel circuit configuration of an even harmonic quadrature mixer (EHQMIX) for direct conversion receivers. In this EHQMIX, a 90 degree phase shifter consists of balance type high pass and low pass filters, and it does not require any circuits connecting to the ground plane. So this configuration is suitable for low cost monolithic IC implementation without any via-holes, because amplitude and phase imbalance, caused by the inductance included in the wires and leads of a package, can be reduced for circuits connected to the ground plane. A developed L-band MMIC achieves good quadrature detection characteristics.

5.8 GHz high sensitivity rectenna array

This paper presents the 5.8 GHz high sensitivity rectenna array with advanced microstrip-type rectifiers and circularly patch antennas achieving a good balance between a high-efficiency and RF weak power operation. The fabricated rectenna element has achieved RF-DC conversion efficiency of 54% at input RF power of 1mW. Furthermore, we have proposed the novel structure which enhances robustness to the breakdown of the diodes when the rectenna elements are arrayed.

RF characteristics of an even harmonic type direct conversion receiver for mobile communications

An even harmonic type direct conversion receiver (EH-DCR) has an advantage of suppressing a degradation of sensitivity caused by interferences such as second order intermodulation and self detected local oscillator noise, so dynamic range of the receiver is as same as that of heterodyne receiver. This paper presents a design condition of the even harmonic quadrature mixer in the EH-DCR. A developed 1.9GHz-band EH-DCR has a sensitivity of ?10ldBm and an intermodulation characteristic of 49dB. These results satisfy the requirements of Personal Handyphone System in Japan.

An X-band even harmonic type direct converter for CDMA satellite communications

This paper describes an X-band even harmonic type direct converter(EH-DC) used in earth stations for CDMA satellite communications. Technical features of this EH-DC are as follows: (a) Carrier leakage of a modulator is extremely low by employing an even harmonic mixer(EH-MIX). (b) High accuracy of a demodulator(low amplitude error and phase error) is achieved by employing an even harmonic quadrature mixer(EH-QMIX). (c) Automatic frequency control(AFC) function is realized by employing a PLL frequency synthesizer driven by a direct digital synthesizer(DDS) with Hz-order tuning. Experimental results in X-band indicate that the proposed EH-DC has no degradation of BER characteristics compared with a heterodyne type transceiver.

Bias circuit for high yield self-bias MMIC amplifier for APAAs

In this paper, a Ka-band self-bias low-noise MMIC amplifier is presented, which is equipped with a bias circuit that compensates for the gain variation of the self-bias amplifier between chips due to process variations. The Ka-band low noise MMIC amplifier, with proposed bias circuit, was designed and manufactured. It was proved that the proposed bias circuit reduced the gain variation between chips from 0.8 dB RMS to 0.3 dB RMS. This amplifier is suitable for active phased array applications.

A Millimeter-Wave Pulse Transmitter with a Harmonic Mixer

Emulsions of oil and water are broken by contacting the emulsions with a quaternized polyalkylene polyamine, e.g., the adduct of 2-hydroxy-3-chloropropyl trimethyl ammonium chloride and a polyethylene polyamine.

Phase decrement type direct frequency synthesizer driven by a DDS

A phase decrement type direct frequency synthesizer with a quadrature mixer driven by a DDS is presented. Phase decrement of a DDS signal can increase the bandwidth of the direct synthesizer. Overflow of a DDS is employed to achieve phase decrement of the signal without adding an extra circuit. A developed 2 GHz-band synthesizer with sub Hz order frequency step achieves 240 MHz bandwidth, frequency switching time of less than 2 /spl mu/s, phase noise of -117 dBc/Hz at 100 kHz offset, and consumption current of 685 mA.