Tauno Vähä-Heikkilä

Millimeter-Wave Identification—A New Short-Range Radio System for Low-Power High Data-Rate Applications

The radio-frequency identification (RFID) concept is expanded to millimeter-wave frequencies and millimeter-wave identification (MMID) in this paper. The MMID concept and a comparison with UHF RFID are presented, showing the limitations and benefits of MMID. Three feasible applications are suggested for MMID, which are: (1) wireless mass memory; (2) an automatic identification system with pointing functionality; and (3) transponder communication with automotive radar. To demonstrate the feasibility of the MMID system, experimental results for both downlink and backscattering-based uplink are presented at 60 GHz.

A 20-50 GHz RF MEMS single-stub impedance tuner

A novel radio-frequency (RF) microelectromechanical system (MEMS) single-stub impedance tuner has been developed. The design is based on combining the loaded line technique with the single-stub topology to obtain wide impedance coverage with high |/spl Gamma//sub MAX/|. The tuner consist of ten switched MEMS capacitors producing 1024(2/sup 10/) different impedances. The design has been optimized for noise parameter and load-pull measurements of active devices and shows excellent measured impedance coverage over the 20-50 GHz frequency range.

Wafer-Level Transfer Technologies for PZT-Based RF MEMS Switches

We report on wafer-level transfer technologies to integrate PZT-based radio frequency (RF) microelectromechanical-systems switches on CMOS. Such heterogeneous integration can overcome the incompatibility of PZT material with back-end-of-the-line (BEOL) CMOS technology. The PZT stack and the transfer process have been optimized to avoid degradation of the PZT actuators during the transfer. In particular, we have optimized the seed layer for the growth of highly oriented PZT on a patterned TiO2-Pt layer, optimized the electrodes structure, and developed an Al2O3 capping layer to prevent degradation of PZT during the transfer process. A full wafer-level transfer process and a selective transfer technology allowing the distribution of RF switches from one source wafer to many receiving wafers has been demonstrated. The latest transfer process demonstrated exhibits great potential for cost optimization of wafer-level transfer of microdevices. In a separate experiment, we have demonstrated the BEOL CMOS compatibility of our integration technique. Switch characterization showed insertion loss of less than 0.5 dB and an isolation better than 30 dB for the 0.4- to 6-GHz frequency range with 15-V actuation voltage.

A reconfigurable 6-20 GHz RF MEMS impedance tuner

A 6-20 GHz reconfigurable triple-stub impedance tuner has been developed. It is based on a 11-switched MEMS capacitor network producing 2/sup 11/ different impedances. The measured and simulated impedance coverage is the widest ever measured to-date from any RF MEMS tuner. This network is most suitable for noise parameters and load-pull measurements of transistors at 6-20 GHz.

A 20-50 GHz reconfigurable matching network for power amplifier applications

A reconfigurable matching network has been developed and it is based on loaded line techniques. It consists of 8 switched MEMS capacitors producing 256 (2/sup 8/) different impedances and is only 1/spl times/2.5 mm in size on a glass substrate. The network is ideally suited to match power amplifiers with 10-20 /spl Omega/ output impedance to 50-60 /spl Omega/ systems at 20-50 GHz. The estimated loss of the network is only 1-1.5 dB at 40 GHz while matching a 10-20 /spl Omega/ load to a 50 /spl Omega/ load. The reconfigurable network can also be used as an impedance tuner in noise parameter and load-pull measurements of active devices at 30-65 GHz.

A wide-band on-wafer noise parameter measurement system at 50-75 GHz

A wide-band on-wafer noise parameter measurement system at 50-75 GHz is presented. This measurement system is based on the cold-source method with a computer-controlled waveguide tuner. Calibrations and measurement methods are discussed and measured results for passive and active on-wafer devices are shown over a 50-75 GHz range. An InP high electron-mobility transistor device is used as a test item for the active device. A Monte Carlo analysis to study measurement uncertainties is also shown. The measurement system is a useful tool in the development and verification of device noise models, as well as in device characterization.

Switched Beam Antenna Based on RF MEMS SPDT Switch on Quartz Substrate

This letter demonstrates a 20-GHz radio frequency microelectromechanical system (RF MEMS)-based electrically switchable antenna on a quartz substrate. Two quasi-Yagi antenna elements are monolithically integrated with a single-pole double-throw (SPDT) MEMS switch router network on a 21 mm times 8 mm chip. Electrical beam steering between two opposite directions is achieved using capacitive MEMS SPDT switches in the router. Port impedance and radiation patterns are studied numerically and experimentally. Measured results show that the switched beam antenna features a 27% impedance bandwidth (S11 = -10 dB), a gain of 4.6 dBi, and a front-to-back ratio of 14 dB at 20 GHz when the control voltage is applied to one of the switch pairs of the SPDT switch.

W-band RF MEMS double and triple-stub impedance tuners

Reconfigurable integrated impedance tuners have been developed for W-band on-wafer noise parameter and load-pull measurement applications. The impedance tuners are based on double and triple-stub topologies and employ 11 switched MEMS capacitors producing 2048 (2/sup 11/) different impedances. Measured |/spl Gamma//sub MAX/| for the double-stub tuner is 0.92 and 0.82 at 75 and 100 GHz from 110 measurements out of 2048 possible impedances, and 0.92 and 0.83 for the triple-stub tuner. To our knowledge, this represents the first W-band integrated impedance tuner to date.

On-wafer noise-parameter measurements at W-band

A wide-band on-wafer noise-parameter measurement setup has been developed for W-band. The system is based on a cold-source method and uses a simple manual impedance tuner. In addition to noise parameters, S-parameters can be measured with the same setup. Using the developed system, noise parameters of an InP high electron-mobility transistor have been measured and results are shown in the 79-94-GHz frequency band. This is the first comprehensive report of noise-parameter measurements made on active devices at W-band.

Hybrid Integrated Micromachined Receiver for 77 GHz Millimeter Wave Identification Systems

This paper presents the design, fabrication and millimeter wave measurements of a w-band (75-110 GHz) hybrid integrated micromachined receiver, an integrated double-folded slot antenna has been manufactured using silicon micromachining techniques. The receiver includes a flip chipped diode, which is used as a detector and modulator to demonstrate a millimeter wave identification (MMID) system, the experimental 77 GHz results show, that backscattering based communication used in radio frequency identification (RFID) is feasible also in the millimeter wave frequency range.