Computing

1
Computing
Prototype Low Power RF Front End
Ian McGregor University of Glasgow Ultrafast
Systems Group ianmcg_at_elec.gla.ac.uk Supervisors
E. Wasige I. Thayne
2
Content of Presentation

• Strategy
• System overview
• Circuits for OOK system
• Other Circuits
• Prototype ICs

Speckled Computing
3
Strategy

• Test System (bench equipment) allows us to
  interact with Strathclyde Uni. at an early stage
  
• Prototype hybrid circuit (cm)
• Integrated circuit/MMIC (mm )

Speckled Computing
4
Conventional Superhet System
Mixers generally use LO powers of 0- 10dBm
(1-10mW)
Speckled Computing
5
On-Off Keying (OOK) System Overview

• Data Waveform used to control Microwave
• Oscillator

0 1 0
Data
Amplifier
Envelope Detector
Speckled Computing
6
Oscillator

• The oscillator is switched off unless
• there is a logic 1 This saves power
• A new oscillator synthesis procedure
• has been developed which gives
• control over efficiency, spectral purity
• and start up time

Speckled Computing
7

• Rx board
• Antenna and Detector (0W). 30mV output
• With 0dBm transmit signal and 12cm
• separation between antennas
• Antenna, amplifier and Detector(7 mW) .
• 0-175mV under above conditions

Circuits for OOK System
Speckled Computing
8
Circuits for OOK System

• Tx board
• Antenna and Oscillator(0.5mW)
• Output power is approximately -10dBm
• Received signal is -25dBm at 7cm separation
• Efficiency is approx. 20
• We hope to improve efficiency to 35 or
• greater

Speckled Computing
9
Experiment

• Tx board Power consumption0.5mW
• Rx board Power consumption0W
• Separation between antennas10cm
• Output of Detector into oscilloscope
• 0 8mV
• Berkeley
• 1.6mW Tx, 0.4mW Rx

Speckled Computing
10
Other Circuits

• Mixer 9dB conversion loss
• when RF2.46GHz and LO2.45GHz
• Monocycle Generator 500pS
• monocycle with good symmetry

Speckled Computing
11
Prototype ICs- Oscillator- 1.7x0.9mm
Speckled Computing
12
Prototype ICs-Amplifier-1.2x0.9mm-17dB Gain
Power Consumption Is 1.6mW (50nm HEMT) For
same Gain using NEC device, 20mW
Speckled Computing
13
Future Work

• Prototype switch and put
• Microstrip circuits onto one board
• Optimise Microstrip circuits
• Start Work on ICs
• In depth questions
• ianmcg_at_elec.gla.ac.uk

Speckled Computing