Metamaterial based power divider for millimeter wave NDT system

Abstract

With globalization, there is a large increase in the amount of people travelling around the world. It is becoming more evident that aircrafts have to work more and yet with higher reliability. In order to reduce downtime, cost and at the same time increase reliability, the aircraft industry have invested a huge sum into Non-Destructive Testing (NDT) technology over the years.

The development of Materials Technology created many stronger, lighter, stiffer and more durable electrically insulating materials that are replacing metals in many applications. These materials cannot be effectively evaluated using the NDT that are commonly used in the industry. A new age microwave and millimeter wave NDT may be the only viable solution.

In order to improve the microwave and millimeter wave NDT, to allow the system to better characterize the defect, a 6-port receiver is proposed to be implemented into the system. A power divider which is the basic building block of the system is studied. The first design utilizes the SIW technique and the second design incorporates interdigital capacitors to realize the meta-material. The designed SIW power divider demonstrated a broadband performance from 11.3 to 25.9GHz with simulated transmissions at about -3.7dB±0.5dB with phase difference of 0º±0.03º between S21 and S31 and occupies only 4cm x 4cm. The interdigital capacitors are introduced at two different locations, at the centre and at the input port of the power divider. Both locations produced a result with multiple fractional bandwidths at 9, 21, 22.5GHz and 9, 12, 21GHz respectively. The proposed power dividers will be implemented into the 6-port receiver and can also fit into a wide range of applications.