Thomas Zwick

SiGe bipolar transceiver circuits operating at 60 GHz

A low-noise amplifier, direct-conversion quadrature mixer, power amplifier, and voltage-controlled oscillators have been implemented in a 0.12-/spl mu/m, 200-GHz f/sub T/290-GHz f/sub MAX/ SiGe bipolar technology for operation at 60 GHz. At 61.5 GHz, the two-stage LNA achieves 4.5-dB NF, 15-dB gain, consuming 6 mA from 1.8 V. This is the first known demonstration of a silicon LNA at V-band. The downconverter consists of a preamplifier, I/Q double-balanced mixers, a frequency tripler, and a quadrature generator, and is again the first known demonstration of silicon active mixers at V-band. At 60 GHz, the downconverter gain is 18.6 dB and the NF is 13.3 dB, and the circuit consumes 55 mA from 2.7 V, while the output buffers consume an additional 52 mA. The balanced class-AB PA provides 10.8-dB gain, +11.2-dBm 1-dB compression point, 4.3% maximum PAE, and 16-dBm saturated output power. Finally, fully differential Colpitts VCOs have been implemented at 22 and 67 GHz. The 67-GHz VCO has a phase noise better than -98 dBc/Hz at 1-MHz offset, and provides a 3.1% tuning range for 8-mA current consumption from a 3-V supply.

60GHz transceiver circuits in SiGe bipolar technology

A 60GHz LNA, direct-downconverter, PA, and 20GHz VCO are built in a 200GHz f/sub t/,/f/sub max/, 0.12/spl mu/m SiGe technology. The 10.8mW LNA has 15dB gain, 3.4-4.4dB noise figure and -8.5dBm IIP3. The down converter has 16dB gain, >50dB LO-RF isolation, and 13.4-14.8dB noise figure. The PA delivers 10dBm at 9dB gain.

Wideband channel sounder with measurements and model for the 60 GHz indoor radio channel

A wideband channel sounder and measurement results for the short range indoor 60 GHz channel are presented. The channel sounder is based on a 1 gigasamples/s dual channel arbitrary waveform generator and A/D converter/software demodulator, which synthesize and detect a baseband PN sequence with 500 MHz bandwidth. A heterodyne transmitter and receiver translate the baseband PN sequence to and from the 60 GHz band. Ten channel measurements taken across the 59 GHz to 64 GHz range are concatenated to provide a continuous channel measurement covering 5 GHz of bandwidth, resulting in 0.2 ns time domain channel impulse response resolution. The dynamic range and maximum sensitivity performance of the channel sounder are discussed in detail. Comparisons of results with a vector network analyzer based system are shown to verify the accuracy of the sounder. In an extensive measurement campaign with vertically polarized omnidirectional antennas, several different rooms (offices, labs, conference rooms and others) in four different buildings have been investigated. Over 700 channel measurements are the basis for a comprehensive characterization of the short range 60 GHz indoor radio channel with omnidirectional antennas. Finally, a simple stochastic static multipath channel model is derived from the measurement results.

Broadband Planar Superstrate Antenna for Integrated Millimeterwave Transceivers

In this paper, a new planar superstrate antenna concept suitable for integration with millimeter wave (mmWave) transceiver integrated circuits (ICs) is presented. The antenna is printed on the bottom of a dielectric superstrate with a ground plane below. The new design provides high bandwidth and high efficiency. Two different examples of the new concept have been designed and manufactured for the 60 GHz industrial scientific medical (ISM) band using folded dipoles. Simulated and measured input impedance matching and far field radiation patterns for both antennas will be shown and discussed. Both designs achieve over 10% bandwidth while maintaining better than 80% efficiency

Probe based MMW antenna measurement setup

A MMW setup is presented for measuring complex impedance and radiation patterns in an anechoic chamber while contacting the antenna with a coplanar probe. Measurement and simulation results of a 60 GHz Vivaldi antenna are shown to demonstrate the setup performance.

Determination of the complex permittivity of packaging materials at millimeter-wave frequencies

The focus of this paper is the determination of the complex permittivity of chip packaging materials at millimeter-wave frequencies. After a broad overview of existing measurement techniques, three methods will be presented that have been established for the dielectric property determination of substrate, as well as mold materials (encapsulants, under-fill, etc.) in the millimeter-wave frequency range. First, the open resonator used here will be briefly described. It allows accurate determination of the dielectric constant and loss of thin sheet substrate materials from below 20 GHz to above 100 GHz. Second, a filled waveguide method is explained in detail. The setup used here can determine the complex dielectric properties of mold materials from 70 to 100 GHz. Third, the method based on covered transmission lines will be described in detail. The used lines allow measurements from below 40 GHz to approximately 90 GHz. Verification of all three methods will be provided by inter-comparison and comparison to values from the literature. Additionally, results for several typical substrate and mold materials that are available for millimeter-wave packaging will be shown and discussed.

WCDMA direct-conversion receiver front-end comparison in RF-CMOS and SiGe BiCMOS

Wide-band code-division multiple-access direct-conversion receiver front-ends have been implemented in both 0.25-/spl mu/m RF-CMOS and SiGe BiCMOS technologies. These circuits have been designed for the same application, radio architecture, and system specifications, allowing relevant comparisons to be made. The front-ends include a bypassable low-noise amplifier, a quadrature downconverter, baseband variable-gain amplifiers, and a local-oscillator frequency divider with output buffers. At 24.5 mA of total current consumption from a 2.7-3.3-V supply, the CMOS front-end has a noise figure of 5.3 dB, in-band third-order intercept point (IIP3) and second-order intercept point (IIP2) of -14 and +20.7 dBm, respectively, and out-of-band IIP3 and IIP2 of >+1.2 and +69 dBm, respectively. Compared to an SiGe front-end consuming 22 mA, the CMOS circuit has a 2-dB higher noise figure, comparable out-of-band linearity, 3-dB higher in-band IIP3, 12-dB lower in-band IIP2, and 7-dB higher LO-to-RF leakage.

Pure-mode network analyzer concept for on-wafer measurements of differential circuits at millimeter-wave frequencies

A measurement concept based on a two-port vector network analyzer has been developed, which enables pure-mode on-wafer measurements of differential circuits in the millimeter-wave frequency range. An error model for the measurement system is derived as required for future calibration algorithms. Based on WR15 waveguide components, together with 1.85-mm coaxial probes, a setup has been built and its amplitude and phase imbalances have been characterized in the frequency range from 50 to 65 GHz.

A direct-conversion receiver integrated circuit for WCDMA mobile systems

A prototype of a 3-V SiGe direct-conversion receiver integrated circuit for use in third-generation (3G) WCDMA mobile cellular systems has been completed. The goal of its design was to minimize current draw while meeting WCDMA receiver rf specifications with margin. The design includes a bypassable low-noise amplifier, quadrature downconverter, and first-stage variable-gain baseband amplifiers integrated on chip. The design is optimized for use with a single-ended off-chip bandpass surface-acoustic-wave filter with no external matching components. The prototype design represents a first step toward a fully integrated monolithic WCDMA/UMTS receiver system-on-a-chip. A rigorous set of performance tests are used to characterize the noise and linearity performance of the packaged IC across its full frequency band of operation. A receiver test-bed system with a software baseband demodulator is used to determine the bit-error-rate performance of the receiver integrated circuit (IC) at sensitivity. Measured results are compared with estimated system performance requirements to determine compliance with key WCDMA rf specifications.

Progress toward a low-cost millimeter-wave silicon radio

This paper discusses the circuits, packaging, and antennas needed to realize a low-cost millimeter-wave transceiver with integrated antenna in silicon technology. The principal application envisioned is in high-speed 60-GHz wireless networks, but the concepts may be applicable to other products as well, such as 77-GHz radar sensors. Circuit results are presented for both 60 and 77 GHz, including an LNA, a highly-integrated direct downconverter, a mixer for a superheterodyne receiver, and a power amplifier. Packaging issues which arise at millimeter-wave frequencies are discussed, and a packaging approach involving a Si IC and a planar antenna in the same package is described. Measurement results for a planar Vivaldi antenna are presented as an example.