O. Ishida

A novel series diode linearizer for mobile radio power amplifiers

A novel series diode linearizer has been developed for mobile radio power amplifiers. It is composed of a series diode with a parallel capacitor, which provides positive amplitude and negative phase deviations with the increase of input power, and can compensate AM-AM and AM-PM distortions of power amplifiers. Applying this linearizer to 1.9 GHz MMIC power amplifier for the Japanese Personal Handy-phone System (PHS), an improvement of adjacent channel leakage power (ACP) up to 5 dB has been achieved for the /spl pi//4-shifted QPSK modulated signal.

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 novel, sub-harmonic pumping direct conversion receiver with high instantaneous dynamic range

A novel sub-harmonic pumping direct conversion receiver (SHP-DCR) employing antiparallel diode pair (APDP) is proposed for high instantaneous dynamic range receivers used in mobile communications. The proposed SHP-DCR can suppress even harmonic mixing products, such as second order intermodulation (IM2) and LO noise that interfere a desired baseband signal. Moreover, the design condition of load resistance is indicated by analytical and experimental approaches for improving diode mixer disadvantages of lower conversion gain and higher LO power. A developed L-band SHP-DCR without a low noise amplifier achieves NF of 18.5 dB, IP3 at input port of 3 dBm and IM2 is below -90 dB in the actual input range.

Even harmonic quadrature modulator with low vector modulation error and low distortion for microwave digital radio

An even harmonic quadrature modulator (EHQMOD) with a low vector modulation error (VME) and low distortion characteristics is presented for small sized digital radio transmitters in microwave. Relationships between modulation characteristics and circuit parameters in the EHQMOD are described by analytical and experimental approaches. In addition, this paper presents an improved configuration of the EHQMOD for a low VME and low distortion characteristics. Developed X-band EHQMOD with root cosine roll-off shaped /spl pi//4 DQPSK achieved 6% of VME without any adjustable circuits and -11 dBm of output power with -50 dBc of leakage power at an adjacent channel. These experimental results verify the effectiveness of analyzed results. The EHQMOD technique indicated in this paper is effective for future high speed digital communications especially in millimeter wave band.

A parallel connected Marchand balun using spiral shaped equal length coupled lines

This paper presents a 6-20 GHz broadband planar monolithic balun. To get a broadband characteristic without narrow spaced coupled transmission lines, a parallel connected Marchand balun with spiral shaped equal length coupled lines are used. A developed monolithic balun achieves the maximum insertion loss of 5 dB including 3 dB power splitting loss from 6 to 20 GHz.

A broadband dielectric diplexer using a snaked strip-line

A diplexer composed of a snaked stripline low-pass filter and a dielectric bandpass filter was developed. The sharper cutoff characteristics of the low-pass filter permit reduction of the element number. In addition, the filters are miniaturized by the use of a high-permittivity dielectric. A 1 GHz-band diplexer with dimensions of 12 mm*50 mm*50 mm was fabricated. This diplexer is suitable for satellite communications.<<ETX>>

Integrated even harmonic type direct conversion receiver for W-CDMA mobile terminals

This paper is the first demonstration of the overall performance of the integrated even harmonic type direct conversion receiver (EH-DCR) with the RAKE receiver. The configuration of the integrated EH-DCR and its evaluation results based on the 3GPP definition are indicated. The RX LTCC module with the SiGe RX-IC, and BiCMOS ABB-IC are developed to achieve high integration of the receiver with filters. The integrated EH-DCR with low second order distortion can achieve high sensitivity and selectivity of the W-CDMA receiver, even with interference due to the transmitting signal. Described evaluation results satisfy the specifications defined by 3GPP. This paper clarifies effectiveness of the integrated EH-DCR for the third generation mobile terminals.

Suppression of multi-path couplings in MCM with a flip-chipped SiGe-MMIC

Techniques to obtain a high isolation property in a multi-chip module (MCM) between pads of a SiGe-MMIC flip-chipped on a low temperature co-fired ceramic (LTCC) are discussed. In such an MCM, there are two coupling paths. One is a path through the LTCC and the other is a path through the MMIC. To improve the total isolation property, structures to reduce the two coupling paths are required because the paths of such leakage are not in series but in parallel. We examined the disposition of several kinds of ground patterns on the LTCC. Also, we devised a metal plate on a bias circuit as a shielding structure on the SiGe-MMIC. The effectiveness of the isolating structures was verified by measuring IIP2 in a receiver MCM with a direct conversion SiGe-MMIC. The IIP2 property has been improved successfully as well as the isolation property.

A millimeter-wave pulse transmitter with a harmonic mixer

This paper describes a millimeter-wave pulse transmitter with a 38 GHz VCO and a harmonic mixer. This harmonic mixer works as a pulse generation switch and a multiplier. By using the harmonic mixer, fluctuation of the load impedance of the 38 GHz VCO can be reduced. The chip size of the developed millimeter-wave harmonic mixer with amplifiers is 1.2 mm/spl times/3.0 mm on a GaAs substrate. To obtain the same fluctuation of the VCO, this proposed configuration can be moderated the isolation value between the VCO and the load about 30 dB compared with the conventional configuration with the switch and the multiplier.

Input impedance of an inhomogeneous side coupler

This paper presents simple formulas for coupler characteristics of an inhomogeneous side coupler. The formula for the input impedance of the coupler explicitly represents that an inductive reactance remains even though the most appropriate characteristic impedance is selected for impedance matching of the coupler. These impedance characteristics are experimentally verified.