Gabor Vinci

The Six-Port in Modern Society

Modern wireless sensing and communication systems are often based on high bandwidth and high carrier frequencies. In the range beyond 100 GHz, common receiver architectures, like active homodyne or heterodyne receivers, have an issue with the amplification needed for mixing. Also, high bandwidth is a problem for these systems. In this context, the six-port receiver is a good alternative, just as well as for lowvolume markets. The six-port concept is based on the additive superposition of the two RF input signals using four different relative phases leading to constructive or destructive interaction. The resulting signals are directly downconverted to baseband by diode circuits operated in detector or mixing mode. The complexvalued information can be easily reconstructed from the four baseband voltages. Historic evolution leads from the reflectometer approach for an alternative vector network analyzer to receivers for sensing and communications. A recent topic is the technology gap in automotive workshops for adjusting the long-range radar sensor of a car. Here, the six-port concept as alignment tool is a good choice, because of its excellent phase resolution. Currently, the integration of the six-port receiver on a MMIC for frequencies beyond 100 GHz is the focus of current work and will be intensified in the future. Will the six-port concept replace common active homodyne and heterodyne receivers? No, but it is a serious alternative for millimeter-wave frequencies and ultrahigh-bandwidth applications in wireless sensing and communication systems. This modern concept can tap new markets for both wireless sensors and sensor networks.

Promise of a Better Position

Industrial automation today is an essential technology underlying our modern society. Advanced positioning and sensor feedback tasks in automation processes often require distance displacement detection, e.g., to measure and track the movement of robots. Furthermore, the detection of mechanical stress in complex industrial machinery through an accurate vibration analysis is often a task of major interest. Therefore, high-resolution distance measurements with short- and long-range positioning are important for a large number of sensing applications and can also be used as a precondition for vibrometer applications. Several automation technologies rely on high precision positioning sensors to track linear as well as rotational movements of various machinery.

Six-Port Radar Sensor for Remote Respiration Rate and Heartbeat Vital-Sign Monitoring

A novel remote respiration and heartbeat monitoring sensor is presented. The device is a monostatic radar based on a six-port interferometer operating a continuous-wave signal at 24 GHz and a radiated power of less than 3

A six-port interferometer based micrometer-accuracy displacement and vibration measurement radar

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Employing six-port technology for phase-measurement-based calibration of automotive radar

. Minor mechanical movements of the patients body caused by the respiration as well as hearbeat can be tracked by analyzing the phase modulation of the backscattered signal by means of microwave interferometry with the six-port network. High-distance measurement accuracy in the micrometer scale as well as low system complexity are the benefits of the six-port receiver. To verify the performance of the system, different body areas have been observed by the six-port radar. The proposed system has been tested and validated by measurement results.

A 77-GHz SiGe Integrated Six-Port Receiver Front-End for Angle-of-Arrival Detection

Displacement detection and vibration measurements are important requirements for automation and mechanical stress diagnosis in diverse industrial environments. Laser interferometry is a widely used technique for these kinds of measurements since it features high-resolution, wide dynamic range and wide frequency response. Another advantage of the laser interferometry technique is contactless diagnosis/sensing which allows remote operations. However this technique is not suitable in harsh environments for instance with the presence of dust or fog which occur in several industrial production sites. In this paper a new contactless radar based vibration measurement technique is presented. It features an RF frontend based on a passive six-port interferometer working at 24 GHz. A dedicated signal processing unit is also presented. The proposed hardware allows to measure with a position accuracy of 0.5 µm.

Six-Port Technology for Traffic Safety

Radar technology is today a key feature for the automotive industry and is becoming of greater importance among most car-producers. Its applications range from cruise control, to pre-crash and parking aid systems. Radar units are already being mounted on several automobiles. Such systems employ high-tech devices and state of the art technology, optimized for robustness and reliability. Specific techniques have been developed to build and install radar devices on board of the vehicles. In particular, precise calibration techniques are being used to set the devices and adjust them so to meet the wanted operation requirements. Radar devices used for adaptive cruise control, installed in front of the vehicle to scan the road ahead in the driving path need a particularly fine adjustment to be as reliable as required by the automotive security standards. Calibration issues in nowadays trimming techniques are causing major problems in the employment of such radar systems. In particular, misalignment of the radar cruise control sensor in respect to the driving axis of the vehicle is leading to false interpretations and reading errors. In this paper, a new, innovative and precise calibration technique is proposed to solve the current calibration problems, focusing on a special microwave measurement technique for enhanced accuracy and reliability.

Dual tone approach for unambiguous six-port based interferometric distance measurements

In this paper an integrated six-port receiver front-end for angle-of-arrival detection of 77-GHz signals is presented. Applications of the circuit are direction finding, automotive radar calibration, or high precision industrial radar. The measurement principle is based on passive superposition of two incident signals and power detection. The circuit features two input amplifiers, a broadband passive six-port network, and four power detectors. The integrated circuit has a power consumption of 95 mW with 5 V supply voltage. It is fabricated in a 200-GHz fT SiGe bipolar technology and occupies only 1028 × 1128 μm2. The circuit operates in a 3-dB bandwidth from 75 GHz to 84 GHz and has a responsivity of 152 kV/W at 80 GHz. A simple calibration method is proposed and all calibration parameters are calculated for different frequency values.

A 77 GHz direction of arrival detector system with SiGe integrated six-port receiver

The market for driver-assistance systems for modern automobiles is rapidly growing. Formerly only provided for the luxury automotive market, these systems are nowadays more and more available for mid- and compact-class vehicles as well. This development is not only limited to the passenger car segment but is also more and more important for commercial vehicles and trucks. Some driving assistance systems have already become mandatory, e.g., the antilock breaking system (ABS). Some governments are currently thinking about requiring automatic distance control by law for heavy trucks. Automatic distance control in combination with an automatic emergency breaking system is one of the rising stars for enhancing traffic safety. Radar- based distance control mostly interacts with cruise control systems and it adapts the speed of the drivers car to the distance to the car or obstacle in front of the vehicle. Furthermore, unavoidable accidents are detected and actions for reducing the effects of the crash are automatically initiated for some systems.

Signal processing strategies for six-port based Direction of Arrival detector systems

This publication shows an approach for absolute, unambiguous distance measurements with a Six-Port radar at 24 GHz. Such an interferometric radar has the drawback of ambiguity problem concerning phase, limiting the measuring distance to half of the used wavelength. This can be solved with the presented dual tone system using the resulting beat frequency between two tones to determine an absolute position within even several wavelengths. In the following, this system will be presented along with simulations and measurements proving the concept.