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In the area of electromagnetic metrology, binary coded excitation signals become more and more important and various binary coded sequences are available. The measurement approach is to assess the impulse response function of a device under test by correlating the response signal with the excitation signal. In order to achieve a high measurement reproducibility as well as a high dynamic range, the generated binary coded signals have to provide low-noise. In this contribution, a low-noise signal generator realized with a field programmable gate array is presented. The performance investigation of different kinds of binary coded excitation signals and different correlation concepts have been practically investigated. With a chip rate of 5 Gchip/s, the generator can be utilized for ultra-wideband applications. In order to allow for a low-noise and long-term stable signal generation, a new clock generator concept is presented and results of phase noise measurements are shown. Furthermore, an algorithm to fast and precisely shifting the time lag between two binary coded signals for correlating excitation and response signals with a hardware correlator is presented. Finally, the realized demonstrator system is tested using two commonly used types of binary coded sequences.

Background Microcalcifications within the fibrous cap of the arteriosclerotic plaques lead to the accrual of plaque-destabilizing mechanical stress. New techniques for plaque screening with small detectors and the ability to differentiate between the smooth and hard elements of plaque formation are necessary. Method Vascular plaque formations are characterized as calcium phosphate containing structures organized as hydroxylapatite resembling the mineral whitlockite. In transmission and reflexion studies with a simple millimeter wave (mm-wave)–demonstrator, we found that there is a narrow window for plaque detection in arterial vessels because of the tissue water content, the differentiation to fatty tissue, and the dielectric property of air or water, respectively. Result The new sensor is based on a sensing oscillator working around 27 GHz. The open-stub capacitance determines the operating frequency of the sensor oscillator. The capacitance depends on the dielectric properties of the surrounding material. The sensor components were completely built up in surface mount technique. Conclusion Completed with a catheter, the sensor based on microwave technology appears as a robust tool ready for further clinical use.

Pseudo-random binary coded excitation signals are being increasingly used for electromagnetic network analysis. Various types of sequences with different correlation properties are available. Unfortunately, nonidealities of real measurement systems, like noise and nonlinearities, degrade the correlation functions. In this contribution a simulator is presented that takes several nonidealities into account. The impact of these nonidealities on two commonly used sequence types, the maximum length sequence (MLS) and the almost perfect autocorrelation sequence (APAS), on the achievable dynamic range (DR) are investigated. In the framework of the presented study, it was taken care that its results can be transferred into hardware requirements.

For the realization of an m-sequence-based reflec-tometer, a correlator performing a pulse compression is necessary in order to determine the impulse response function (IRF) of a device under test (DUT). Using a hardware correlator, a time delayed version of the m-sequence transmit signal is required. In this contribution, a concept for the generation of two m-sequences with a fast and precisely adjustable time lag between them is presented. Programmable linear feedback shift registers (LFSRs) are used for generating the m-sequences. The desired time lag is realized by using different initial states of the LFSRs. To guarantee that the time lag is set within one clock period, a select pulse generator (SPG) has been designed and implemented into the system. The concept has been validated by means of measurements using a realized demonstrator setup. According results show the fast time lag adjustment. Furthermore, reflection measurements have been performed with different coupler architectures and a coaxial cable with a length of 20m. Results obtained with two different couplers are compared regarding the achievable dynamic range.

In this contribution, an m-sequence-based system for network analysis is presented. This system is based on a new correlator concept, which combines the advantages of a hardware and a software correlator. In hardware, the multiplication of the received signal with a time lagged version of the excitation signal is performed. This enables a correlation for desired time lags resulting in a short measurement time, especially for long m-sequences. In software, integrate and dump (I&D) is performed, which enables a precise integration over one sequence length or integer multiples thereof, resulting in a high side maxima suppression. Furthermore, compared to a pure software correlator, the requirements with regard to the sample and hold stage are significantly lower. First, the fundamental properties of m-sequences and of the realized correlator are discussed. Afterwords, results with optimized measurement time and dynamic range of the system, derived from numerical simulations, are presented. Furthermore, to experimentally validate the system concept, a demonstrator has been realized. Measurement results showing the achievable dynamic range are presented.

In this contribution, a high efficiency class-E power amplifier is presented, which is optimized with respect to heat a variable plasma load at 10MHz. First of all, the design of the class-E amplifier is demonstrated. Therefore, after the fundamental design equations, the dimensioning of amplifier's lumped elements is presented. Furthermore, simulations and measurements are performed in order to verify the functionality and efficiency. During this, two high power MOSFETs from Microsemi and IXYS are compared. An efficiency of 90.7% at 507W output power and 50Ω load is achieved. The resistance of the plasma load can change between 200Ω and 300Ω. Therefore, an optimized matching network, which provides an almost constant output power of ±1% in the desired load resistance range, is presented.

In this contribution, we present latest measurement results on human blood permittivity within the frequency range from 10GHz to 40GHz. Because bio sensor testing inside of real human blood is often critical, we propose a substitution material that is nonhazardous and unperishable. Furthermore, corresponding parameters for the advanced Cole-Cole model are presented for all investigated materials.

This contribution shows a sensor design for the intravascular differentiation of vulnerable and calcified plaques. A measurement concept based on the reflection of an oblique incident electromagnetic wave at the dielectric interface between blood and plaque is discussed. Therefore, the indispensable dielectric properties of both materials are presented. For a catheter embedded solution the sensor is optimized with respect of small geometries and a smooth cylindrical shape. The optimization and verification are performed by means of 3D electromagnetic wave simulations. Furthermore, a broadband measurement concept is presented, which provides additional information for the plaque type differentiation.

In this contribution, a novel measuring method for the differentiation of intra vascular plaque types is presented. The proposed method operates contact free because of the mm-wave based approach. Fundamentals concerning material properties of blood and plaque, and electromagnetic barrier reflections are discussed. Furthermore, a test setup consisting of a miniaturized sensor setup is introduced that clarifies the measuring concept. Additionally, results of 3D electromagnetic field simulations as well as first measurements ex situ performed on non-human genetic materials are shown and discussed in detail.