It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

On the capacity of a cellular CDMA system

Two 4-bit active phase shifters integrated with all digital control circuitry in 0.13-mum RF CMOS technology are developed for X- and Ku-band (8-18 GHz) and K-band (18-26 GHz) phased arrays, respectively. The active digital phase shifters synthesize the required phase using a phase interpolation process by adding quadrature-phased input signals. The designs are based on a resonance-based quadrature all-pass filter for quadrature signaling with minimum loss and wide operation bandwidth. Both phase shifters can change phases with less than about 2 dB of RMS amplitude imbalance for all phase states through an associated DAC control. For the X- and Ku-band phase shifter, the RMS phase error is less than 10o over the entire 5-18 GHz range. The average insertion loss ranges from to at 5-20 GHz. The input for all 4-bit phase states is typically at -5.4 plusmn1.3 GHz in the X- and Ku-band phase shifter. The K-band phase shifter exhibits 6.5-13 of RMS phase error at 15-26 GHz. The average insertion loss is from 4.6 to at 15-26 GHz. The input of the K-band phase shifter is at 24 GHz. For both phase shifters, the core size excluding all the pads and the output 50 Omega matching circuits, inserted for measurement purpose only, is very small, 0.33times0.43 mm2 . The total current consumption is 5.8 mA in the X- and Ku-band phase shifter and 7.8 mA in the K-band phase shifter, from a 1.5 V supply voltage.

/pdf/0-13-mu-m-cmos-phase-shifters-for-x-k-u-and-k-band-phased-4p47id1bq8.pdf

0.13- $\mu$ m CMOS Phase Shifters for X-, K u -, and K-Band Phased Arrays

ii To the most beloved people in my life,

Novel Approaches to the Design of Phased Array Antennas

This paper demonstrates an 8-element phased array receiver in a standard 0.18-mum SiGe BiCMOS (1P6M, SiGe HBT ft ap 150 GHz) technology for X- and Ku-band applications. The array receiver adopts the All-RF architecture, where the phase shifting and power combining are done at the RF level. With the integrations of all the digital control circuitry and ESD protection for all I/O pads, the receiver consumes a current of 100 ~ 200 m A from a 3.3 V supply voltage. The receiver shows 1.5 ~ 24.5 dB of power gain per channel from a 50 Omega load at 12 GHz with bias current control, and an associated NF of 4.2 dB (@ max. gain) to 13.2 dB (@ min. gain). The RMS gain error is < 0.9 dB and the RMS phase error is < 6deg at 6-18 GHz for all 4-bit phase states. The measured group delay is 162.5 plusmn 12.5 ps for all phase states at 6-18 GHz. The RMS phase mismatch and RMS gain mismatch among the eight channels are < 2.7deg and 0.4 dB, respectively, for all 16 phase states, over 6-18 GHz. The 8-element array can operate instantaneously at any center frequency and with a wide bandwidth (3 to 6 GHz, depending on the center frequency) given primarily by the 3 dB gain variation in the 6-18 GHz range. To our knowledge, this is the first demonstration of an All-RF phased array on a silicon chip with very low RMS phase and gain errors at 6-18 GHz. The chip size is 2.2 times 2.45 mm2 including all pads.

An X- and K u -Band 8-Element Phased-Array Receiver in 0.18- $\mu{\hbox{m}}$ SiGe BiCMOS Technology

A 57-64-GHz low phase-error 5-bit switch-type phase shifter integrated with a low phase-variation variable gain amplifier (VGA) is implemented through TSMC 90-nm CMOS low-power technology. Using the phase compensation technique, the proposed VGA can provide appropriate gain tuning with almost constant phase characteristics, thus greatly reducing the phase-tuning complexity in a phased-array system. The measured root mean square (rms) phase error of the 5-bit phase shifter is 2° at 62 GHz. The phase shifter has a low group-delay deviation (phase distortion) of +/- 8.5 ps and an excellent insertion loss flatness of ±0.8 dB for a specific phase-shifting state, across 57-64 GHz. For all 32 states, the insertion loss is 14.6 ± 3 dB, including pad loss at 60 GHz. For the integrated phase shifter and VGA, the VGA can provide 6.2-dB gain tuning range, which is wide enough to cover the loss variation of the phase shifter, with only 1.86° phase variation. The measured rms phase error of the 5-bit phase shifter and VGA is 3.8° at 63 GHz. The insertion loss of all 32 states is 5.4 dB, including pad loss at 60 GHz, and the loss flatness is ±0.8 dB over 57-64 GHz. To the best of our knowledge, the 5-bit phase shifter presents the best rms phase error at center frequency among the V-band switch-type phase shifter.

60-GHz 5-bit Phase Shifter With Integrated VGA Phase-Error Compensation

A CMOS wideband cascaded variable gain amplifier (VGA) with a temperature-independent exponential gain control characteristic is presented in this paper. The exponential gain control function is realized using parasitic bipolar transistors and a control signal converter. The bandwidth is extended using an inductive peaking technique for high-frequency operations. The gain of the VGA varies from -38.8 to 55.3 dB in relation to the control voltage that varies from 0 to 1.8 V. The bandwidth of the proposed VGA is approximately 900 MHz with a gain control range of 94.1 dB. The proposed VGA includes a dc offset cancellation loop to avoid amplification of the dc offset. The VGA is powered by 1.8 V with 11.4 mA. The VGA chip including bondpads occupies an area of 850 mum times 490 mum.

/pdf/a-wideband-cmos-variable-gain-amplifier-with-an-exponential-2clgg6bdq5.pdf

A Wideband CMOS Variable Gain Amplifier With an Exponential Gain Control

A digital 5-bit phase shifter at Ku-band is presented, which is implemented with 0.18-mum RFCMOS technology. n-MOSFET switches and top metal microstrip lines with a first-metal ground allow the phase shifter to have small insertion losses. The proposed 90deg phase shifter utilizing a parallel resonator exhibits broad-band characteristics. All of the circuit components are derived to obtain a minimum phase variation at the operation frequency band. A bridged-T type phase shifter is also analyzed in view of parallel resonance using an ideal equivalent-circuit model. The conditions of the circuit elements are derived in an analytic form, which are used to obtain the broad-band phase characteristics. The fabricated 5-bit phase shifter demonstrates an overall rms phase error less than 12deg from 9 to 15 GHz. Insertion losses of 14.5 dB plusmn 0.5 dB and return losses less than 14 dB are obtained for 32 states at 12 GHz. The proposed 90deg phase shifter has performed a phase shift of 92.3degplusmn3.2deg over 9-15 GHz

https://koasas.kaist.ac.kr/bitstream/10203/1572/1/000234657600038.pdf

Ku-band MMIC phase shifter using a parallel resonator with 0.18-/spl mu/m CMOS technology

Band MMIC Phase Shifter Using a Parallel

A new quadrature balanced voltage controlled oscillator (B-VCO) is presented. The quadrature and single B-VCO with identical components are implemented in 0.18 /spl mu/m CMOS technology. The quadrature B-VCO has lower phase noise, higher oscillation frequency and higher figure of merit (FOM) than the single B-VCO. The measured phase noise values of the single and quadrature VCO are -114.83 and -116.67 dBc/Hz at the offset frequencies of 1 MHz at the center frequency of 10.21 and 10.81 GHz, respectively. Both VCO cores consume about 8.8 mA from a 1.8 V supply. The FOM of 183 and 185 dB are achieved in the quadrature and single VCO respectively.

/pdf/an-x-band-cmos-quadrature-balanced-vco-iym4o0q3oy.pdf

An X-band CMOS quadrature balanced VCO

This paper describes a Tx module for IMT2000 applications consisting of an up-conversion mixer and a variable-gain driver amplifier. The up-conversion mixer, based on the Gilbert active topology has a power gain of 4.8 dB and consumes 15-mA current from a 3-V supply. The variable-gain driver amplifier comprises a gain-controlled stage of the current steering structure and a common emitter stage, and has a variable-gain range of over 30 dB with 30.3-mA current consumption. The Tx module achieves a gain error of less than 1.2 dB over a 30-dB gain range, an output IP3 of 25 dBm, and an output PI dB of 7.4 dBm at the maximum gain of 24.5 dB. It occupies 1.0 /spl times/ 1.2 mm.

Hui Dong Lee

Papers

A Wideband CMOS Variable Gain Amplifier With an Exponential Gain Control

Ku-band MMIC phase shifter using a parallel resonator with 0.18-/spl mu/m CMOS technology

Band MMIC Phase Shifter Using a Parallel

An X-band CMOS quadrature balanced VCO

A SiGe BiCMOS transmitter module for IMT2000 applications