Embedded Radio Frequency Sensor System into The Transceiver Architecture and Enhanced Communication Capability in Adverse Environment

• Author / Creator

  Saghlatoon, Hossein

• Sensors are an essential part of Internet-of-Things (IoT) and wireless-sensor-network. They are the main block for sensing and obtaining information about the environmental parameters or materials of concern. From industrial applications for safety improvement to biomedical, health monitoring and smart homes for quality assessment, the sensors play a significant role. The desired parameter alters the characteristics of a sensor which later is converted to digital data for post-processing and decision making.

  Amongst different categories and types of sensor, radio frequency (RF) and microwave ones have recently attracted more attention due to the advantages that can be obtained through the frequency response monitoring. Still, there is a long path from what has been proposed in the literature to commercial versions of RF/Microwave sensors.

  Most of the studied RF/Microwave sensors lack from the conversion of the frequency domain sensing data to digital values. For this purpose, either expensive frequency monitoring equipment is required or the data should be post-processed to extract the sensing information. This stays as the main obstacle for the commercialization of low-cost, low-power, and fast response sensors. In addition, since the sensing is done by altering the frequency response of the device, no mechanisms have been proposed to compensate for the effect of the parameter under test on the circuit. To the author's knowledge, not many investigations have been done on the conversion of RF/Microwave sensing data to digital values and compensation of frequency-response deviation due to sensing as well as the integration of RF sensors into the communication system.

  In this dissertation, different configurations of sensor system embedded into the conventional communication architectures have been proposed in which the antenna acts as the main radiating elements and passive RF/Microwave sensor. In the first system, the extraction of sensing data is done at the receiver using a simple, low-cost and low power, zero crossing detector. This system is adaptable to communication nodes where the carrier frequency of the system can be in a certain range and does not have to be fixed. The second system comprises a sensing scheme embedded into a fixed frequency digital modulator in which the parameter under test alters the frequency response of the antenna. The antenna loads the modulator causing the error of the feedback loop in the frequency stabilization section to increase depending on the loading strength. The error is a control voltage forcing the local oscillator to operate at the original frequency and can be converted to digital data using an analog-to-digital converter (ADC) and be sent alongside the pilot data. These systems are implemented based on RFID standards and conventional modulation scheme as an example and are not limited to this application at all. The implementation of the RF/Microwave sensing system into the transceiver architectures in the proposed manner does not require any more power consumption; therefore, the power consumption of the system is preserved. In addition, in certain applications such as on-body or metal-proximity, the communication range of the sensing system diminishes significantly due to their adverse effect on electromagnetic waves. It is required to design a system in order to improve the communication range passively. Another aspect of this dissertation is to mitigate this obstacle for the magnetically coupled communication system.

• Subjects / Keywords

  • Antenna
  • RF
  • Sensor

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-14th-6t65

• License

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