G. Whyte

A channel model for wireless sensor networks in gas turbine engines

A narrowband channel model (2.4 GHz to 2.5 GHz) for wireless sensors deployed over the external surfaces of a gas turbine engine is reported. The model is empirical and based on a series of transmission loss measurements over the surface of a gas turbine engine.

Different Feeding Geometries for Planar Elliptical UWB Dipoles, and the Excitation of Leakage Current

This paper presents an assessment of the impact of feeding geometry and leakage current on the performance of several types of printed elliptical UWB dipoles. Using simulation and experimental verification this paper investigates the impact via field analysis, S-parameters, and pulse transmission. The UWB dipoles investigated are; a microstrip-fed UWB dipole, that had unpredictable behaviour due to the feed, which excited leakage current down the feed cable and, as a result, distorted the pulse. To minimise the leakage current, three other UWB dipoles were investigated. These were a CPW-fed UWB dipole with slots, a hybrid-feed UWB dipole, and a tapered-feed UWB dipole.

Empirical modelling and simulation of transmission loss between wireless sensor nodes in gas turbine engines

Transmission loss measurements between a grid of hypothetical WSN node locations on the surface of a gas turbine engine are reported for eight frequencies at 1 GHz intervals in the frequency range 3.0 to 11.0 GHz. An empirical transmission loss model is derived from the measurements. The model is incorporated into an existing system channel model implemented using Simulink as part of a wider project concerning the development of WSNs for the testing and condition monitoring of gas turbine engines.

Parasitic Moding Influences on Coplanar Waveguide Passive components at G-Band Frequency

In this work the paper presents the effect of parasitic moding on the mm-wave (140-220GHz) performance of coplanar waveguide (CPW) components on GaAs substrates as a function of substrate thickness and layout geometries. It is observed that mm-wave energy leakage especially at 220GHz is quite significant, i.e. as high as 9 dB for a standard short structure fabricated on 630 mum

Integrated 915 MHz dual-patch circularly polarized antenna for Suaineadh space web experiment

The University of Glasgow, UK, and KTH (Royal Institute of Technology), Sweden, have collaborated on the Suaineadh (Suaineadh is a Scots Gaelic word meaning “twisting”) experiment [1] to be onboard a REXUS [2] rocket. The experiment objectives are to deploy a space-web [3] [4] using centrifugal forces and to stabilize the web once full deployment has been achieved.

Low complexity, 165 µW, 5 Mbit/s wideband radio front-end with range of several meters

This paper details the design, implementation, simulation and measurement of an ultra low power, low complexity, wideband RF front end. The RF transceiver front end is suitable for short range, relatively high data rate applications (5 Mbit/s). The transmitter consists of an SRD - based pulse generator. The pulse generator is triggered by bursts of low frequency carrier. The narrow bursts of carrier are used to signal a data ‘1’ and cause the pulse generator to output a series of narrow, wide bandwidth, impulses. The output RF impulses are sent through a pair of wideband, high gain, Vivaldi antennas. The received pulses are envelope detected by a wideband active FET detector. A SPDT FET-based switch is used to allow antenna sharing and consumes approximately 15 µW. The transmitter is passive and requires a drive signal of 0.5 mW. The overall power consumption of the receiver is 150 µW. A non linear model running inside ADS is used to model the SRD-based pulse generator. The transceiver is the lowest complexity, lowest power wideband RF front end published and has a range of several meters.

Low complexity, low power, 10 GHz super-regenerative transceiver

In this paper a 10 GHz quasi-Hybrid/MMIC super-regenerative transceiver/antenna chip is presented. The circuit is the highest frequency super-regenerative transceiver presented in the literature and is amongst the lowest power - certainly the lowest power at X-band frequency. The chip is fabricated on GaAs substrate and uses a MMIC process for the passive components and an RFMD PHEMT chip device bonded into the circuit for the active components. The transceiver chip measures 10 × 10 mm and consumes 0.75 mW Tx and 0.9 mW Rx. When mounted into a pcb carrier substrate containing antenna, bias circuitry and low pass filtering the board measures 26 × 42 mm and operates over a range of 1 m.