Osami Ishida

L-band internally matched Si-MMIC front-end

A 1.9 GHz-band internally matched Si-MMIC front-end, fabricated in standard 0.8 /spl mu/m BiCMOS process, was developed. This IC front-end contains a MOSFET T/R switch, a two-stage BJT low noise amplifier (LNA), and a down converter BJT mixer. Since the circuits are monolithically integrated on a low resistivity Si substrate, the coplanar waveguide (CPW) type spiral inductors are used to reduce the dielectric loss of on-chip matching circuits. The T/R switch has measured insertion loss of 2.5 dB and isolation of 25.5 dB at 0/3 V control voltage. The two-stage LNA has gain of 17.1 dB and noise figure (NF) of 2.9 dB at 2 V, 4 mA dc supply. The mixer has conversion gain of 5.9 dB and NF of 15 dB at 2 V, 1.7 mA dc supply. The measured performance of the fabricated Si-MMIC front-end indicates the possibility of application to mobile communication handset terminals.

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.

A passive-type even harmonic quadrature mixer using simple filter configuration for direct conversion receiver

A passive-type even harmonic quadrature mixer using simple filter configuration for direct conversion receiver is presented. All circuits in the mixer are composed of passive elements. Diplexers of this mixer consist of simple high pass and low pass filters enough to realize a mixer with small size. This mixer is suitable for a mobile handset, because no DC consumption is required and it is easy to design and manufacture from its simple configuration. A developed mixer achieved good RF characteristics for direct conversion receivers.

Impedance matching in active integrated antenna receiver front end design

The active integrated antenna (AIA) concept has been realized in the design of integrated amplifier front end, which enables its applications in novel adaptive antenna systems. To address the problem of mismatch between antenna element and amplifier, we present the matching renditions of both gain impedance and noise figure minimum impedance. In addition, the application of these principles is demonstrated in the design of ultra-compact helical AIA receiver front end for operation at 2.1 GHz. Amplifier simulation and measurements have been carried out to confirm the design procedure. It is shown that the proposed configuration can be successfully used in novel wireless handsets.

Transfer characteristic of IM/sub 3/ relative phase for a GaAs FET amplifier

Measured transfer characteristic of relative phase of the third order intermodulation distortion (IM/sub 3/) of a GaAs FET amplifier is described. The measurement system and method are also described. For drives in the weakly nonlinear region, the measured relative phase of IM/sub 3/ is equal to that of carriers, and agrees with the analysis result based on Volterra-series representation. For drives in the saturation region, the measured relative phase of IM/sub 3/ versus the input power is larger than that of carriers relative phase. The measured results and the measurement method are useful for the design and adjustment of predistortion type linearizer for GaAs FET high power amplifiers.

EM analysis of PBG substrate microstrip circuits for integrated transmitter front end

In this work, electromagnetic analysis of a novel photonic bandgap (PBG) substrate microstrip line circuit is presented and its applications in an integrated antenna amplifier transmitter front end are discussed. The method-of-moments based Sonnet Suite has been used for full-wave 3D electromagnetic simulation of the microstrip on a high-density substrate having rectangular air blocks. It is shown that a single row of air blocks consisting of only 3-5 elements of optimized dimensions produce a very steep and wide (up to 10 GHz) bandgap for the microstrip mode. The results obtained demonstrate that such a structure has high potential for designing novel low-pass and band-pass filters and integrated amplifier tuning elements. The transmission-line-circuit method has been applied in obtaining analytical conditions of stopband and passband for the circuit considered. The proposed structure can be mass-produced by micro drilling in a conventional high-density substrate.

1.9 GHz/5.8 GHz-band on-chip matching Si-MMIC low noise amplifiers fabricated on high resistive Si substrate

The use of high resistivity Si substrates, instead of the conventional low resistivity Si substrate, enables one to reduce the loss of spiral inductor for the on-chip matching circuit by 61% at 1.9 GHz and by 78% at 5.8 GHz and to improve gain and noise performance of the BJT. These improvements are explained as the reduction of dielectric loss of substrate by referring to equivalent circuit model extraction. The fabricated 1.9 GHz-band on-chip matching LNA performs 13.4 dB gain, 1.9 dB NF with 2 V, 2 mA DC power and 5.8 GHz-band LNA performs 6.9 dB gain, 3.3 dB NF with 3 V, 3 mA DC power.The use of high resistive Si substrate, instead of conventional low resistive Si substrate, enables one to reduce the loss of spiral inductor for on-chip matching circuit by 61% at 1.9 GHz and by 78% at 5.8 GHz, and to improve gain and noise performance of the BJT. These improvements are explained as the reduction of dielectric loss of substrate by referring to equivalent circuit model extraction. The fabricated 1.9 GHz-band on-chip matching LNA performs 13.4 dB gain, 1.9 db NF with 2 V, 2mA d.c. power and 5.8 GHz-band LNA performs 6.9 dB gain, 3.3 dB NF with 3 V, 3 mA d.c, power.

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.

A novel grounded coplanar waveguide with cavity structure

This paper presents a grounded coplanar waveguide (GCPW), which is useful in RF-MEMS devices in order to effectively reduce noise from neighboring transmission lines. The GCPW structures demonstrated here were fabricated by front-surface-only processes on a single silicon wafer. A silicon nitride membrane supports the coplanar waveguide, which is located above a ground plane formed on an etched silicon cavity We found that the insertion losses of the 50-/spl Omega/ GCPWs with a 26-/spl mu/m-wide signal line and a 6-/spl mu/m-deep cavity do not exceed 0.4 dB/mm up to 20 GHz, which agreed with the simulated loss. The demonstrated maximum depth of metallized cavity is 30 /spl mu/m, which enables the GCPWs loss to be as low as 0.08 dB/mm at 20 GHz.

A high efficiency feedforward amplifier with a series diode linearizer for cellular base stations

A feedforward power amplifier (FFPA) with a series diode linearizer using a bias feed resistance is presented. To improve overall feedforward amplifier efficiency, a series diode linearizer is used to provide main amplifier linearization. FFPA efficiency optimization design considering FET efficiency and linearity trade-off has been demonstrated. The developed FFPA achieved the high efficiency of 10% and output power of 45.6 dBm at 10 MHz offset ACLR -50 dBc under W-CDMA 2 carriers signal.