Przemyslaw Korpas

Electromagnetic Inspection of Carbon-Fiber- Reinforced Polymer Composites With Coupled Spiral Inductors

This paper presents a new type of an electromagnetic sensor for nondestructive testing of carbon-fiber-reinforced polymer composites. The sensor utilizes coupled planar spiral inductors operating typically in the range of 10-500 MHz. The method proposed here shows some similarity to the eddy current technique, but as will be shown, the principles of operation are different as the sensitivity to defects is mostly due to the magnetic field components tangential to the surface of a material. It is shown that the method is applicable to 3-D inspection of carbon-fiber-reinforced composites widely employed in the aerospace industry.

Non-destructive testing of carbon-fiber-reinforced polymer composites with coupled spiral inductors

A new type of an electromagnetic sensor for nondestructive testing of carbon-fiber-reinforced polymer composites, based on coupled planar spiral inductors, is presented. The sensor operates in the range of 10 - 500 MHz, where the largest detectability of buried defects is expected. The new method shows some similarity to the eddy currents technique but the principles of operation are different as the sensitivity to possible defects is mostly due to a magnetic field horizontal to the surface of the material. One of advantages is the applicability of the method to a three-dimensional inspection of the carbon-fiber-reinforced composites.

Multichannel measurement system for non-destructive testing of carbon-fiber-reinforced polymer composites

This paper presents a customized measurement system for non-destructive testing of carbon-fiber-reinforced polymer composites. The measurement principle is based on changes in the magnitude of a transmission coefficient between two planar coupled spiral inductors caused by defects buried in the composite under test. The system consists of several measurement channels to speed up the scanning process performed with the array of sensors. Selected experimental results are shown.

Effects of applying a frequency and phase-shift efficiency optimisation algorithm to a solid-state microwave oven

The systematic progress in RF high power semi-conductor technology opens chances for the magnetron replacement by solid-state microwave sources in the area of domestic microwave ovens, which may result in a completely innovative product on the market. To fully utilize benefits given by this new architecture, RF sources must be controlled by a dedicated optimization algorithm. This paper presents results of applying a basic efficiency optimization algorithm in case of a simple cuboidal two-port cavity.

Automatic Split Post Dielectric Set-up for Measurements of Substrates and Thin Conducting and Ferroelectric Films

We have developed an inexpensive computer controlled microwave oscillator system that enables quick and automatic measurements of the complex permittivity with a specific split post dielectric resonator (SPDR). It is based on a phase-locked loop Microwave Voltage Controlled Oscillator intended for the Q-factor and the resonance frequency measurements of SPDR. Multipoint resonance curve fitting procedure allows accurate Q-factor determination. The only external information that is necessary for the complex permittivity determination of a dielectric substrate or a ferroelectric film is the thickness of the sample under test. We compare the complex permittivity measurement results on few dielectric samples employing Vector Network Analyser and our measurements set-up. We also present measurement results of the sheet resistance and resistivity of epitaxial GaN films deposited on sapphire substrates.

An ultrawideband 1 to 6 GHz 0-IF radio receiver with 500 MHz of instantaneous bandwidth

This paper is related to the project of an ultrawideband radio receiver operating between 1 and 6 GHz with instantaneous bandwidth of 500 MHz. A single frequency conversion (0-IF) architecture is based on analog I/Q demodulator (ADL5380) and two channel 14-bit analog-to-digital converter (AD9680). Preliminary measurements of the receiver have been performed and presented in the paper. Key results include: noise figure NF < 7.5 dB, dynamic range over 62 dB (enhanced by frontend and baseband leveling circuitry), high linearity: IIP3 > 21 dBm.

Low phase noise synthesizer optimized for wideband 0-IF radio receiver

In this paper the performance of two wideband PLL frequency synthesizers realized with ADF5355 and HMC833 chips respectively has been compared. Both of them were investigated as a local oscillator for 0IF receiver operating from 1 GHz to 6 GHz. In order to provide required harmonics level below -40 dBc the final solution is based on the ADF5355 followed by a switched bank of four low pass filters. The phase noise level is better than -90 dBc @ 1 kHz and spurious are lower than -70 dBc.