Background

 A phase shifter is a device used for changing the phase angle of the RF signal. Phase shifter has broad applications in communications, radar, instrumentation, accelerators, missile attitude control, signal modulation and demodulation. Phase shifter is a key enabling technology for phased array antennas, where multiple phase shifters are used to provide the phase increments required to steer the radiation beam. Such antennas are widely used in mobile base stations, satellites and radar systems. 

The main challenge of designing phase shifters is that they need to provide a wide angle shift with minimum insertion losses. Usually, their losses increase with the amount of phase shift, which limits the performance of the device or its application. For example, conventional diode-based phase shifters suffer from high insertion losses and poor power handling capability.

Additionally, most of the phase shifters provide different phase delay at different frequencies over a wide frequency band. This is also referred to as ‘dispersion’. To minimise the dispersion, conventional phase shifters have to operate over a narrow bandwidth which again limits their applicability.

Technology Overview

The researchers at the University of Birmingham have developed a new tunable linear phase shifter which boasts a combination of low insertion loss (almost independent of the phase), high phase resolution, and low dispersion. The ‘passive’ phase shifting element also promises capability to handle high power. The phase shifter is based on a new design of substrate integrated waveguide structures, has simple circuitry and is easy to fabricate.

Benefits

Example performance parameters:

• Low loss: 1.1 ± 0.1 dB with a figure-of-merit of 163.6°/dB (at 11.5 GHz)
• High phase resolution: 1.68° (over the 0-180° phase shift range)
• Linear phase increment
• Phase deviation with frequency (dispersion) is within ±2°over 10 - 12.5 GHz (22%) and within ±5° over 9 - 13 GHz (36%).
• Passive phase shifting element
• Simple circuitry
• Potentially high-power handling capability 

Applications

• Phase array antennas
• Satellite
• Defence (missile altitude control)
• Radars
• Accelerators

Opportunity

The University is mostly looking for a licensee.