<p>In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. </p><p>The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured. </p><p>The main goal of this Master thesis was to design a connection, that would be useful in practice. The connections should be easy to manufacture and have a good performance. They should also have a high tolerance for manufacturing errors. </p><p>The main part of this report contains descriptions of different designs. The designs are presented together with simulated and measured results. </p><p>The report contains designs based upon coplanar waveguides and a phase shifting technique. The result shows that designs that are using coplanar waveguides are good. The phase shifting technique has some limitations and need to be developed further.</p>

<p>The task of the project was to evaluate a differential phase shift keying demodulation technique by replacing a Mach-Zehnder interferometer receiver with an optical filter (Fiber Bragg Grating). Computer simulations were made with single optical transmission, multi channel systems and transmission with combined angle/intensity modulated optical signals. The simulations showed good results at both 10 and 40 Gbit/s. Laboratory experiments were made at 10 Gbit/s to verify the simulation results. It was found that the demodulation technique worked, but not with satisfactory experimental results. The work was performed at Eindhoven University of Technology, Holland, within the framework of the STOLAS project at the department of Electro-optical communication.</p>

In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured. The main goal of this Master thesis was to design a connection, that would be useful in practice. The connections should be easy to manufacture and have a good performance. They should also have a high tolerance for manufacturing errors. The main part of this report contains descriptions of different designs. The designs are presented together with simulated and measured results. The report contains designs based upon coplanar waveguides and a phase shifting technique. The result shows that designs that are using coplanar waveguides are good. The phase shifting technique has some limitations and need to be developed further.

The task of the project was to evaluate a differential phase shift keying demodulation technique by replacing a Mach-Zehnder interferometer receiver with an optical filter (Fiber Bragg Grating). Computer simulations were made with single optical transmission, multi channel systems and transmission with combined angle/intensity modulated optical signals. The simulations showed good results at both 10 and 40 Gbit/s. Laboratory experiments were made at 10 Gbit/s to verify the simulation results. It was found that the demodulation technique worked, but not with satisfactory experimental results. The work was performed at Eindhoven University of Technology, Holland, within the framework of the STOLAS project at the department of Electro-optical communication.

Direct-Sequence Code Division Multiple Access (DS-CDMA), over the last few years, has become a popular technique and finds a place in many modern communication systems. The performance of this technique is closely linked to the signature (or spreading) sequences employed in the system. In the past, there have been many successful attempts by research groups to construct families of signature sequences that offer the potential gains promised by theoretical bounds. In this thesis, we present constructions of families of signature sequences over the AM-PSK and QAM alphabet with low correlation. In this thesis, we construct a family of sequences over the 8-ary AM-PSK constella- tion, Family AOpt(16) that is asymptotically optimal with respect to the Welch bound on maximum magnitude of correlation for complex sequences. The maximum magnitude of correlation for this family, θmax, is upper bounded by √N , where N is the period of the sequences. The 8-ary AM-PSK constellation is a subset of the 16-QAM constellation. We also construct two families of sequences over 16-QAM, Family A16A, and Family A16,B , with the maximum magnitude of correlation upper bounded by √2√N . We construct a family, A(M 2), of sequences over the 2m+1-ary AM-PSK constellation of period N = 2r- 1 and family size (N + 1)/2m-1 . The 2m+1-ary AM-PSK constellation is a subset of the M 2-QAM constellation with M =2m . The maximum nontrivial normalized correlation parameter is bounded above by θmax < a √N where a ranges from 1.34 in the case of M 2 = 16 to √5 for large m. Apart from low correlation values, the family possesses several interesting and useful features. In Family A(M 2), users have the ability to transmit 2m bits of data per period of the spreading sequence. The sequences in Family A(M 2) are balanced; all points from the 2m+1-ary AM-PSK constellation occur approximately equally often in sequences of long period. The Euclidean distance between the signals assigned to a particular user in A(M 2), corresponding to different data symbols, is larger than the corresponding value for the case when 2m+1-PSK modulation and spreading is used. Perhaps most interestingly, Family A(M 2) permits users on the reverse link of a CDMA system to communicate asynchronously at varying data rates by switching between different QAM constellations. Family A(M 2) is compatible with QPSK sequence families S(p) in the sense that the maximum correlation magnitude is increased only slightly if one adds sequences from (p) S(p)\ S(0) to Family A(M 2). We also construct families of sequences over AM-PSK that tradeoff data rate per sequence period and θmax for a given family size. We have extended the construction of sequences over AM-PSK constellation to construct sequences over the M 2-QAM constellation for M =2m . The QAM sequence families, Families (AM 2), have size, data rate and minimum squared Euclidean distance same as the corresponding AM-PSK construction but have higher values of θmax. Also included in the thesis are constructions for large families of sequences over the M 2-QAM alphabet.

No description available.

Most of today’s microwave circuits are designed for specific function and specialneed. There is a growing trend to have flexible and reconfigurable circuits. Circuitsthat can be digitally programmed to achieve various functions based on specific needs. Realization of high frequency circuit blocks that can be dynamically reconfigured toachieve the desired performance seems to be challenging. However, with recentadvances in many areas of technology these demands can now be met. Two concepts have been investigated in this thesis. The initial part presents thefeasibility of a flexible and programmable circuit (PROMFA) that can be utilized formultifunctional systems operating at microwave frequencies. Design details andPROMFA implementation is presented. This concept is based on an array of genericcells, which consists of a matrix of analog building blocks that can be dynamicallyreconfigured. Either each matrix element can be programmed independently or severalelements can be programmed collectively to achieve a specific function. The PROMFA circuit can therefore realize more complex functions, such as filters oroscillators. Realization of a flexible RF circuit based on generic cells is a new concept.In order to validate the idea, a test chip has been fabricated in a 0.2μm GaAs process, ED02AH from OMMICTM. Simulated and measured results are presented along withsome key applications like implementation of a widely tunable band pass filter and anactive corporate feed network. The later part of the thesis covers the design and implementation of tunable andwideband highly linear LNAs that can be very useful for multistandard terminals suchas software defined radio (SDR). One of the key components in the design of a flexibleradio is low noise amplifier (LNA). Considering a multimode and multiband radiofront end, the LNA must provide adequate performance within a large frequency band.Optimization of LNA performance for a single frequency band is not suitable for thisapplication. There are two possible solutions for multiband and multimode radio frontends (a) Narrowband tunable LNAs (b) Wideband highly linear LNAs. A dual bandtunable LNA MMIC has been fabricated in 0.2μm GaAs process. A self tuningtechnique has also been proposed for the optimization of this LNA. This thesis alsopresents the design of a novel highly linear current mode LNA that can be used forwideband RF front ends for multistandard applications. Technology process for thiscircuit is 90nm CMOS.

No description available.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Bit errors often occur in a wireless communications link when impairments alter the transmitted signal. It is advantageous to be able to predict how well a system will tolerate transmission problems. This paper details laboratory performance measurements and comparisons in terms of evaluating configurations of a digital receiver for Feher patented Quadrature Phase Shift Keying (FQPSK-B) demodulation. The transmitted signal is subjected to calibrated levels of impairments while the receiver performance is monitored in real-time.

Cavity ring-down spectroscopy has been used over the last twenty years as a highly sensitive absorption spectroscopic technique to measure light attenuation in gases, liquids, and solid samples. An optical cavity is used as a multi-pass cell, and the decay time of the light intensity in the cavity is measured, thereby rendering the techniques insensitive to light intensity fluctuations. Optical waveguides are used to build the optical cavities presented in this work. The geometries of such waveguides permit the use of very small liquid sample volumes while retaining the advantages of cavity ring-down spectroscopy. In this thesis cavity ring-down measurements are conducted, both, in the time domain and by measuring phase-shifts of sinusoidally modulated light, and the two methods are theoretically connected using a simple mathematical model, which is then experimentally confirmed. A new laser driver, that is compatible with high powered diode lasers, has to be designed to be able to switch from time domain to frequency domain measurements. A sample path length enhancement within the optical cavity is explored with the use of liquid core waveguides. The setup was optimised with respect to the matrix liquid, the geometrical matching of waveguide geometries, and the shape of liquid core waveguide ends. Additionally, a new technique of producing concave lenses at fibre ends has been developed and the output of a general fibre lens is simulated. Finally, liquid core waveguides are incorporated into a fibre-loop ring-down spectroscopy setup to measure the attenuation of two model dyes in a sample volume of <1 µL. The setup is characterized by measuring concentrations of Allura Red AC and Congo Red from 1 µM to a limit of detection of 5 nM. The performance of the setup is compared to other absorption techniques measuring liquid samples. / Thesis (Ph.D, Chemistry) -- Queen's University, 2013-04-23 14:08:16.33