P. Kangaslahti

Resistive HEMT mixers for 60-GHz broad-band telecommunication

We report two resistive mixers, i.e., a balanced and a balanced image-rejection (IR) mixer for the 60-GHz frequency range. A compact and wide-band method for the local-oscillator (LO) power division is presented. The 56-GHz LO signal, which propagates in a coplanar-waveguide mode, is divided in between the lines of two spiral baluns. Consequently, a smooth and compact transition from even-to-odd propagation mode and an in-phase power division for two singly balanced unit mixers is achieved. As a result, the developed IR mixer occupies only 1.41mm/sup 2/ of chip area. The balanced design achieved 11.5 dB of conversion loss from 57 to 67 GHz with a fixed IF of 5.3 GHz. The corresponding LO suppression was better than 34 dB with 8 dBm of LO power. The IR mixer achieved better than 19 dB of IR ratio and better than 36 dB of LO suppression for an RF frequency from 57 to 66 GHz. The corresponding conversion loss varies from 13 to 16 dB. The measured 1-dB compression point of the IR mixer was at a -13-dBm output power level and the third-order intercept point was at a 4-dBm level.

Miniaturized artificial-transmission-line monolithic millimeter-wave frequency doubler

Millimeter-wave signals are typically generated by frequency multiplication in modern single-chip or multichip module (MCM) systems. Consequently, the multiplication efficiency, spurious rejection, and size of the frequency multiplier ultimately limit the integration level and cost of these systems. This paper points to the size reduction of millimeter-wave frequency doublers by evaluating artificial transmission lines (ATLs) as a means to minimize the size of the low-impedance shunt stubs. As a result, we developed a 40-GHz frequency doubler, which used only 0.6-mm/sup 2/ area on a monolithic microwave integrated circuit. Despite the area minimization, the doubler exhibited state-of-the-art conversion loss of 1 dB over 10% bandwidth and rejected the fundamental frequency signal by more than 20 dB over 25% bandwidth. Reported herein is the novel simulation of the frequency doubler with active harmonic loads. Included in this paper are theoretical evaluation and simulation of ATLs with models for lumped components and verification of the results by electromagnetic simulation. Due to the high efficiency, low area requirement, and over 20-dB rejection of the fundamental signal, this miniaturized ATL frequency doubler can be used as a building block in the generation of local-oscillator signals in single-chip and MCM millimeter-wave systems.

Low noise amplifiers in InP technology for pseudo correlating millimeter wave radiometer

This decade will be very important for cosmology due to several missions to measure the cosmic microwave background radiation. These measurements require highly sensitive radiometers operating over a very wide frequency spectrum. The millimeter wave radiometers are best developed as pseudo correlating radiometers due to the inherent stability and high sensitivity of this instrument, To miniaturize the size and power consumption of these radiometers we have developed the critical low noise amplifier and phase switch MMICs using high-performance InP technologies. The low noise amplifiers achieved record 2.3 dB noise figure over the 60-80 GHz frequency band at room temperature and less than 25 K noise temperature at 20 K ambient temperature. These MMICs form the building blocks for 70 GHz highly sensitive correlating radiometers, that are needed e.g. in the ESA Planck mission.

Low phase noise signal generation circuits for 60 GHz wireless broadband system

Demand for large capacity and low installation costs explains the extensive use of millimeter wave frequencies in digital wireless broadband communications. In digital wireless systems, the achievable bit error rate is strongly dependent on low phase noise in millimeter wave signal sources. The low phase noise can be achieved with frequency multiplication of high performance microwave oscillators. This study aims to reduce the size of millimeter wave frequency doublers by evaluating the spiral transmission line transformer as a means to minimize the size of the balun. As a result we developed a millimeter wave frequency doubler, which used only 0.3 mm/sup 2/ area on MMIC. We also present theoretical evaluation and simulation of these novel balanced frequency doublers. Furthermore, a 60 GHz frequency doubler was designed to demonstrate the frequency doublers in a millimeter wave signal source with ultra low phase noise.

A set of integrated circuits for 60 GHz radio front-end

This paper describes results obtained within the MMIC research activity at the Helsinki University of Technology (HUT). These MMICs were developed for a 60 GHz broadband radio front-end. A set of circuits is reported including power, low noise amplifiers, mixers and signal generation circuits. They have been fabricated with a commercially available 0.15 /spl mu/m GaAs pseudomorphic HEMT technology. Finally, the performance of the circuits was measured at 60 GHz frequency: The power amplifier has 14 dBm output compression point and 15.5 dB small signal gain. The low noise amplifier exhibits 24 dB of gain with 3.5 dB noise figure and the up-conversion mixer circuit has 12.7 dB of conversion loss.

W-Band On-Wafer Noise Parameter Measurements

Several current and planned space missions for earth observation and astronomy require very low noise receivers at W-band. Key components in W-band low noise receivers are the InP low noise amplifiers (LNA). The design of LNAs is a greatly dependent at the availability of good noise models for the devices used in the LNAs. To characterise devices at W-band an on-wafer noise parameter set-up has been developed and is presented here. Using the set-up the noise parameters of an InP HEMT in the frequency band 79-94 GHz have been measured. These are the first reported noise parameter measurements of active devices at W-band. The measurement set-up is based on the cold-source method.

Monolithic Artificial Transmission Line Balanced Frequency Doublers

Artificial transmission lines, realized using standard passive components of the foundry library, were utilized to design 180-degree baluns for millimetre wave frequency doublers. Monolithic integration of the complete doubler was achieved on extremely small chip area, 0.6mm2. However, the performance of the frequency doubler was not sacrificed, since the operating frequency bandwidth was 30 %. These results show the suitability of this new technique for integration of several of the functions of a transmit/receive unit economically on a very small area on chip.

Integrated power amplifier for 60 GHz wireless applications

This paper presents an integrated power amplifier for the 60 GHz frequency range. The amplifier was fabricated with a commercially available 0.15 /spl mu/m gate length pseudomorphic HEMT process. The output stage consists of two 6/spl times/35 /spl mu/m PHEMTs, forming a total output periphery of 420 /spl mu/m. The MMIC amplifier was simulated, fabricated and measured both on-wafer and in a split block package. The amplifier was characterized using linear and nonlinear methods. The odd mode stability was carefully analyzed. Large-signal scattering parameters were measured with on-wafer probes. The measured gain was 13.4 dB and 1 dB output compression point was at +17 dBm power level using 3.0 V supply voltage. The AM/AM and AM/PM characteristics were extracted from the large-signal S-parameter results. Finally, the amplifier chip was mounted in a split block package, which has WR-15 wave guide input and output interface. The measured results show 12.5 dB small-signal gain and better than 8 dB return losses in input and output for the packaged amplifier chip.

Wideband Radio Channel Sounder Extension to 60 GHz Frequency Range

To evaluate the performance of 60 GHz frequency range wireless networks, propagation measurements have to be performed. This paper presents our millimeterwave channel sounder design based on direct sequence waveform. Delay resolution is about 17 ns and dynamic range about 40 dB. Continuous routes up to several hundred meters can be measured taking four samples per wavelength. This paper includes laboratory test results of the system.

Power amplifiers for 60 GHz WLAN applications

This paper presents MMIC power amplifiers for 60 GHz broadband radio applications. These amplifiers have been fabricated using a commercially available 0.15 /spl mu/m GaAs pseudomorphic HEMT technology. The output compression point of the prototype three stage single ended amplifier was +15 dBm and the small signal gain, 12 dB. The improved version achieved 15.5 dB linear gain and +14 dBm compression point using 3 V supply voltage.