A novel reconfigurable variable gain amplifier for a multi-mode multi-band receiver

This paper presents a novel approach for designing a reconfigurable variable gain amplifier（VGA） for the multi-mode multi-band receiver system RF front-end applications.The configuration,which is comprised of gain circuits,control circuit,DC offset cancellation circuit and mode switch circuit is proposed to save die area and power consumption with the function of multi-mode and multi-band through reusing.The VGA is realized in 0.18μm CMOS technology with 1.8 V power supply voltage providing a gain tuning range from 5 to 87 dB when the control voltage varies from 0 to 1.8 V.The 3 dB bandwidth is about 80 MHz for all levels of control voltage（all gains）.Also,the DC offset cancellation circuit can effectively suppress DC offset to a value of less than 40 mV at the output regardless of the input.The overall power consumption is less than 3 mA,and die area is 705×100μm^2.

A single-ended wideband reconfigurable receiver front-end for multi-mode multi-standard applications in 0.18μm CMOS

This paper presents a reconfigurable RF front-end for multi-mode multi-standard(MMMS) applications. The designed RF front-end is fabricated in 0.18 μm RF CMOS technology. The low noise characteristic is achieved by the noise canceling technique while the bandwidth is enhanced by gate inductive peaking technique. Measurement results show that, while the input frequency ranges from 100 MHz to 2.9 GHz, the proposed reconfigurable RF front-end achieves a controllable voltage conversion gain(VCG) from 18 dB to 39 dB. The measured maximum input third intercept point(IIP3) is-4.9 dBm and the minimum noise figure(NF) is 4.6 dB. The consumed current ranges from 16 mA to 26.5 mA from a 1.8 V supply voltage. The chip occupies an area of 1.17 mm^2 including pads.

A multi-mode multi-band RF receiver front-end for a TD-SCDMA/LTE/LTE-advanced in 0.18-μm CMOS process

A fully integrated multi-mode multi-band directed-conversion radio frequency （RF） receiver front-end for a TD-SCDMA/LTE/LTE-advanced is presented. The front-end employs direct-conversion design, and consists of two differential tunable low noise amplifiers （LNA）, a quadrature mixer, and two intermediate frequency （IF） amplifiers. The two independent tunable LNAs are used to cover all the four frequency bands, achieving sufficient low noise and high gain performance with low power consumption. Switched capacitor arrays perform a resonant frequency point calibration for the LNAs. The two LNAs are combined at the driver stage of the mixer, which employs a folded double balanced Gilbert structure, and utilizes PMOS transistors as local oscillator （LO） switches to reduce flicker noise. The front-end has three gain modes to obtain a higher dynamic range. Frequency band selection and mode of configuration is realized by an on-chip serial peripheral interface （SPI） module. The front- end is fabricated in a TSMC 0.18-μm RF CMOS process and occupies an area of 1.3 mm2. The measured double- sideband （DSB） noise figure is below 3.5 dB and the conversion gain is over 43 dB at all of the frequency bands. The total current consumption is 31 mA from a 1.8-V supply.

Multi-mode multi-band power amplifier module with high low-power efficiency

Increasingly, mobile communications standards require high power efficiency and low currents in the low power mode. This paper proposes a fully-integrated multi-mode and multi-band power amplifier module （PAM） to meet these requirements. A dual-path PAM is designed for high-power mode （HPM）, medium-power mode （MPM）, and low-power mode （LPM） operations without any series switches for different mode selection. Good performance and significant current saving can be achieved by using an optimized load impedance design for each power mode. The PAM is tapeout with the InGaP/GaAs heterojunction bipolar transistor （HBT） process and the 0.18-μm complementary metal-oxide semiconductor （CMOS） process. The test results show that the PAM achieves a very low quiescent current of 3 mA in LPM. Meanwhile, across the 1.7-2.0 GHz frequency, the PAM performs well. In HPM, the output power is 28 dBm with at least 39.4% PAE and 240 dBc adjacent channel leakage ratio 1 （ACLR1）. In MPM, the output power is 17 dBm, with at least 21.3% PAE and -43 dBc ACLR1. In LPM, the output power is 8 dBm, with at least 18.2% PAE and -40 dBc ACLR1.

Analysis and design of a high-linearity receiver RF front-end with an improved 25%-duty-cycle LO generator for WCDMA/GSM applications

A rally integrated receiver RF front-end that meets WCDMA/GSM system requirements is presented.It supports SAW-less operation for WCDMA.To improve the linearity in terms of both IP3 and IP2,the RF front-end is comprised of multiple-gated LNAs with capacitive desensitization,current-mode passive mixers with the proposed IP2 calibration circuit and reconfigurable Tow-Thomas-like biquad TIAs.A new power-saving multi-mode divider with low phase noise is proposed to provide the 4-phase 25%-duty-cycle LO.In addition,a constant-g_m biasing with an on-chip resistor is adopted to make the conversion gain invulnerable to the process and temperature variations of the transimpedance.This RF front-end is integrated in a receiver with an on-chip frequency synthesizer in 0.13μm CMOS.The measurement results show that owing to this high-linearity RF front-end,the receiver achieves -6 dBm IIP3 and better than ＋60 dBm IIP2 for all modes and bands.

Frequency-Diversified Space-Efficient Radiating Surface Using Convolved Electric and Magnetic Currents for Highly Dense Multiband Antenna-Frontend Integration

We propose and investigate a methodology based on convolved electric and magnetic currents for the generation of multi-band responses over a space-shared radiating surface.First,a single wideband antenna operation principle based on inter-leaved dipole and slot modes is studied and analyzed using full-wave simulations followed by a qualitative time domain analysis.Subsequently,a 2×2 dual-band radiating unit is conceived and developed by closely arranging single wideband antennas.In this case,multimode resonances are generated in a lower frequency band by a proper convolving and coupling of the magnetic and electric currents realized in the gaps between the antennas and on the surface of the antennas,respectively.This methodology can be deployed repeatedly to build up a self-scalable topology by reusing the electromagnetically(EM)connected radiating surfaces and gaps be-tween the radiating units.Due to the efficient reuse of the electromagnetic region for the development of multiband radiation,a high aperture-reuse efficiency is achieved.Finally,as a proof of concept,a 2×4 dual-band array operating in Ku-and Ka-bands is devel-oped and fabricated by a linear arrangement of the two developed radiating units.Our measurement results show that the proposed antenna array provides impedance and gain bandwidths of 30%and 25.4%in the Ku-band and 10.65%and 8.52%in the Ka-band,respectively.

Institute of Microelectronics, Tsinghua University, Beijing 100084, China

A reconfigurable multi-mode direct-conversion transmitter （TX） with integrated frequency synthe sizer （FS） is presented. The TX as well as the FS is designed with a flexible architecture and frequency plan, which helps to support all the 433/868/915 MHz ISM band signals, with the reconfigurable bandwidth from 250 kHz to 2 MHz. In order to save power and chip area, only one 1.8 GHz VCO is adopted to cover the whole frequency range. All the operation modes can be regulated in real time by configuring the integrated register-bank through an SPI interface. Implemented in 180 nm CMOS, the FS achieves a frequency coverage of 320-460 MHz and 620- 920 MHz. The lowest phase noise can be -107 dBc/Hz at a 100 kHz offset and-126 dBc/Hz at a 1 MHz offset. The transmitter features a 10.2 dBm peak output power with a ＋9.5 dBm 1-dB-compression point and 250 kHz/500 kHz/1 MHz/2 MHz reconfigurable signal bandwidth.