DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

Abstract-This contribution analytically studies the influence of IQ mismatch on the performance of multiple-antenna orthogonal frequency division multiplexing (OFDM) systems based on the zero-IF architecture. First a system model for such a multiple-input multiple-output (MIMO) OFDM system experiencing both transmitter (TX) and receiver (RX) IQ imbalance is derived. This is used to obtain analytical expressions for the probability of error in symbol detection for MIMO OFDM systems in Rayleigh faded multipath channels. The derived results can be used to find matching specifications for the TX-and RX-branches for different multicarrier MIMO systems. It is concluded that in fading channels RX IQ imbalance is on average more destructive than TX IQ imbalance. Additionally, it is concluded that the addition of extra RX antennas is beneficial to reduce the dependence on RX IQ imbalance, but increases at the same time the impact of TX IQ imbalance.

Background/purpose Millimeter‐wave reflectometry is a potentially interesting technique to analyze the human skin in vivo in order to determine the water content locally in the skin. Purpose of this work is to investigate the possibility of skin‐tissue differentiation. In addition, it addresses the influence of the pressure of the probe on the skin, the influence of an air gap between probe and skin as well as the influence of a bandage between probe and skin. Methodology Reflection coefficients at various positions on the skin are measured in the 40–60 GHz range and the examined effects are quantified in terms of magnitude and phase of the reflection coefficient. Also, the possibility to perform tissue differentiation is quantified. Results It is indicated that differentiation of skin tissue can be performed on the basis of the magnitude of the reflection coefficient provided that no air gap exists between probe and skin. The influence of probe pressure can be substantial, in particular for phase measurements. The presence of an air gap between probe and skin reduces the differentiation capability of the considered measurement technique, whereas a bandage between probe and skin did not significantly affect the differentiation power. Conclusion The results of this work confirm the potential of millimeter‐wave reflectometry for determination of the water content in skin tissue which may lead to interesting applications as early detection of skin cancer and through‐bandage monitoring of wounds.

No abstract

The dielectric properties of glucose solved in pure water as well as in a physiological solution have been measured. The results are considered in the context of noninvasive diabetes control. At least 0.002 percent measurement accuracy is required to achieve the same accuracy as obtained with traditional finger pricking.

DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

Millimeter‐wave (mm‐wave) reflectometry is a potentially interesting technique to analyze the human skin. We examined the possible influence of the probe pressure on the reflection coefficient obtained with a mm‐wave empty open‐ended wave‐guide probe when used for diagnosis of human skin. It is demonstrated that this influence can be considerable.© 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2341–2342, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27074

Fig. 3 shows the circuit parameters of a series L-C network that reproduce the n = 2 susceptance characteristic in Fig. 2. The magnitude of the adaptive change in the L-C parameters has been reduced (compared to the single IS solution in Fig. 3). The absolute values are also more practical for high-frequency circuits. Practical considerations concerning adaptive Salisbury screen:The physical structure of the adaptive IS will depend on the frequency band over which it is to operate. At radio frequencies, the IS (being an active two-dimensional version of an impedance string [6]) will comprise discrete circuit components. At microwave frequencies, an adaptive, possibly fractal, frequency selective surface (FSS) becomes more appropriate. A fractal FSS geometry has advantages owing to its multiband impedance characteristic. The adaptive network may comprise an electronic or optical switch to effect a step change in the L-C parameters of an IS. Smaller yet continuous change may be achieved through the use of varactor circuit elements. The use of semiconductor switching elements results in switching time constants of the order of seconds, so that for most applications the absorber will have the electromagnetic characteristics of a broadband material. The condition that Y=O at the resistive card is necessary for all incident angles and polarisations. Since the apparent electrical depth of the absorber changes with incidence angle, the IS susceptance that produces Y= 0 also changes. Nonetheless, the same physical structures that yield broadband absorption at normal incidence can be retained for broadband absorption at other incidence angles and polarisations (with appropriate scaling of R in (2)). However, if the angle of incidence is arbitrary, R must also be adaptive. Conclusions:Adaptive absorbers circumvent the fundamental limitations that limit the absorption bandwidth of thin low-frequency absorbers. An adaptive ultra-broadband Salisbury screen can be designed for perfect absorption at normal or oblique incidence angles, though if the incident wave arrives at an arbitrary angle, the resistive card and the IS must have, respectively, adaptive resistive and adaptive reactance properties.