Rashed H. Bhuiyan

Design and Application of Surface Wave Sensors for Nonintrusive Power Line Fault Detection

This paper describes a novel conformal surface wave (CSW) launcher that can excite electromagnetic surface waves along unshielded power line cables nonintrusively. This CSW launcher can detect open circuit faults on power cables. Unlike conventional horn-type launchers, this CSW launcher is small, lightweight, and cost effective, and can be placed easily on a power cable. For a nonintrusive open fault detection, the error is <; 5% when the cable length is <; 10 m, which is comparable with other direct-connect fault-finding techniques. For a cable length of 15.14 m, 7.6% error is noted. Besides cable fault detection, the potential applications of the proposed launcher include broadband power line communication and high-frequency power transmission.

Novel surface wave exciters for power line fault detection and communications

A novel conformal surface wave (CSW) exciter is introduced which can excite electromagnetic (EM) surface waves along unshielded power line cables non-intrusively. The CSW exciter is small, cost effective and can be easily placed on a power cable compared to conventional monopole type launchers or horn type launchers. Besides cable fault detection, the potential applications of the proposed exciter include broadband power line (BPL) communication and high frequency power transmission.

A Miniature Energy Harvesting Device for Wireless Sensors in Electric Power System

A novel energy harvesting device called the energy coupler is proposed which can provide power to small wireless sensors in a power system. The energy coupler when coupled electromagnetically to a nearby current carrying conductor scavenges ac power from the conductor. The proposed energy coupler converts the harvested ac power into dc using a passive voltage multiplier circuit. The design of the energy coupler is such that the dc power obtained is adequate to charge a miniature 1.2-V rechargeable battery. It is demonstrated that the energy coupler is capable of delivering 10 mW of dc power to a 50-Ω load. An analytical model is also presented which agrees well with measurement results within a margin of error of 10%.

Concrete Moisture Content Measurement Using Interdigitated Near-Field Sensors

The efficacy of a meander and a circular interdigitated sensor in detecting and measuring the moisture present in wet concrete samples is demonstrated. Analytical, simulation, and measurement results of interelectrode capacitance for samples with different moisture contents show good agreement. As moisture content increases from 0% to 6%, the interelectrode capacitance that predicts the moisture content increases by 126.4% for the meander sensor and 187% for the circular sensor. Regression analysis of the measured data demonstrates that for moisture content less than 6% the relationship between the measured capacitance and the percent moisture content is predominantly linear.

Proximity Coupled Interdigitated Sensors to Detect Insulation Damage in Power System Cables

Proximity coupled interdigitated sensors are introduced to detect insulation damage in power system cables. A new empirical model for interdigitated sensors with conducting backplane is developed. The validity of this newly proposed model is verified by comparing the results obtained from the new model with simulation and experimental results. It is shown that while the existing models fail to correspond to the simulation and experimental results due to the presence of the conducting backplane, the new model can fairly approximate the effect of the backplane on the sensor performance. A meander and a quarter-circular sensor are designed for insulation damage detection. Measurement results on planar dielectric materials, as well as practical power line cables are presented to demonstrate the usefulness of these sensors. Such sensors placed on microrobots crawling along power cables could lead to the potential autonomous monitoring of an electric power system.

A double meander PIFA with a parasitic metal box for wideband 4G mobile phones

A novel double meander PIFA with a parasitic metal box is proposed which can operate from 698 MHz to 960 MHz and is suitable for multimedia and voice communication in 4G mobile phones. A metal box in the vicinity of the PIFA is placed to improve the bandwidth and shift the operating frequency band lower. The antenna has good radiation pattern coverage over the whole frequency band and the cross polarization level is below −15 dB.

Wireless power delivery under concrete for sensors

Wireless power delivery to sensor antennas embedded under concrete is studied at frequencies near 13.5 MHz. Measured results reveal that power loss of about 9 dB is expected for 20 mm thick old dry concrete while 17.3 dB is expected for 30 mm thick freshly made concrete.

An interdigitated PIFA for RFID data communication and dielectric sensing applications

The performance of an interdigitated type device as a sensor and as a PIFA is studied. The proposed device operates as a sensor by applying a 1 kHz sinusoidal signal at its driving electrode and as an antenna by applying or receiving 915 MHz band RFID signals also at the same driving electrode. It is demonstrated that the proposed device can detect the changes in the dielectric constant of a material under test and also can work as a PIFA with 30 MHz bandwidth and optimum radiation pattern coverage for RFID application.

A novel multi-element fractal PIFA with wide pattern coverage for 915 MHz RFID wireless sensors

The performance of a single-element PIFA and a multi-element PIFA are studied and compared to determine their suitability in RFID sensor tags for placement on rotating platforms. Each antenna operates in the 915 MHz frequency band and occupies a maximum area of 90 by 90 sq. mm. It is demonstrated that using the multi-element PIFA in place of the single-element PIFA, 33.33% bandwidth enhancement and superior radiation pattern coverage can be obtained.

A new crossed staircase dipole antenna for 915 MHz RFID application

A crossed meander antenna and a crossed staircase antenna are studied for RFID based sensor networks. Both antennas are designed to operate in the unlicensed 915 MHz frequency band. Each antenna occupies a printed circuit board area of 152 by 102 sq. mm. It is demonstrated that the crossed staircase antenna has low mutual coupling (<-30 dB), overall good radiation pattern coverage, and high peak gain (2.1 dBi) suitable for RFID based sensor networks.