This thesis aims to design transformer-based balanced passive components with high performance and compact size using CMOS and printed-circuit¡Vboard (PCB) technologies. A CMOS parallel-combining transformer (PCT) incorporating a planar trifilar transformer is presented to realize power combining and impedance transformation at the same time. In addition, a CMOS Wilkinson power combiner with a planar bifilar transformer is proposed to enhance isolation between two combining ports. Several transformer coupled balun designs with an overlay winding structure are carried out on FR4 and Duroid substrates. These designs uses a rather symmetric layout to achieve a superior balance performance and a multilayer configuration to create the transmission zeros in the out-of-band response. Finally, a CMOS transformer balun is implemented with a bandpass filter passband which is designed according to the coupled resonator filter theory. This passband can restrict the bandwidth usage for the balun to improve the common-mode rejection ratio (CMRR) within the passband.

Yes / A design of dual-band balanced antenna structure operating in the 700 and 2600MHz LTE bands is studied and investigated. The overall dimensions of the radiator are 50 × 18 × 7 mm3 allowing it to be easily concealed within mobile handsets. A broad-band balun is designed and integrated with the antenna handset in order to provide the feeding network and perform the measurements of the antenna radiation performance. Prototypes of proposed antenna with and without balun are fabricated and verified. The simulated and practical results with and without the handheld effects in terms of reflection coefficient, power gain and radiation pattern, are studied and shown reasonable agreement. / H2020

This thesis at first introduces planar transformers and their applications to RF circuits. A method is given to validate the impedance transformation and calculate the insertion loss for a transformer with unequal turn windings. A physical lumped-element model has been established for a planar transformer-based balun implemented using integrated passive device technology. This thesis next presents CMOS power combiner designs with two differential ports and one single-ended port. Such designs equivalently integrate two baluns and one single-ended power combiner into a single circuit and therefore have the advantages of saving chip area and reducing insertion loss. In addition, the designs consider an annular ground structure to achieve lower insertion loss or better balance property. Finally, this thesis presents a balun using a stacked coil transformer in an organic build-up substrate. For this purpose, a complete design flow and an impedance matching technique have been given.

This thesis presents a brief introduction to microwave components and technology. It also presents two novel dual-band designs, their analysis, topology, simulation and fabrication. In chapter 2, a novel dual-band bandpass filter using asymmetric stub-loaded stepped-impedance resonators (SLSIRs) operating at 1 and 2.6 GHz is shown. This type of design applies suitable arrangements to improve the filter’s performance. Then, in chapter 3, a novel dual-band balun (transforms unbalanced input signals to balanced output signals or vice versa) operating at 1.1 and 2 GHz with flexible frequency ratios is presented, which has more advantages in microwave applications. Then, conclusion and future works are discussed in chapter 4.

In this thesis, we propose a miniaturized LTCC balanced filter that integrates bandpass filter (BPF) and balun. In order to reject interferences, we have the transmission zero of out-band by extra capacities and inductances in the prototype of Second-Order BPF. On the other hand, we miniaturize the balun by revising the length of couple-line with four shunt capacities. The practice size of the miniaturized balanced filter is 2.0mm x 1.25mm x 0.95mm.The insertion and return losses are less than -2.5dB and -20dB over operating frequency band, respectively. The phase difference is less than 5 ¢X, and the amplitude difference is within -0.5dB in operating frequency band. The size is the smallest in the similar commercial product and relative journal.

This thesis is mainly composed of two parts. The first part is to introduce the planar transformer-based circuits and their applications. The mixed-mode S parameters and the grounding effects for planar transformers are discussed. A physical model has been developed for modeling the planar transformers. In the second part, a new coil winding technique for planar transformers has been presented to realize a high-efficiency planar transformer with arbitrary turn ratio for power-split/combine and phase-shift applications. Especially, the power-split/combine architecture based on a planar transformer of cellular shape is first presented in this thesis, enabling various kinds of passive components to be widely realized using the integrated passive device processes. As an example, this thesis proposes a design procedure for high-efficiency balun component. Firstly, design a high Q transformer that considers the load impedance effects. Secondly, design the ground reference for un-balanced signal on the virtual ground symmetry axis for balanced signals. Thirdly, design impedance matching networks for minimizing un-balanced and balanced port return losses. Then, a high performance planar transformer-based balun design can be done.

In general, Dual-Band technology enables microwave components to work at two different frequencies. This thesis introduces novel dual-band microwave components and their applications. Chapter 2 presents a novel compact dual-band balun (converting unbalanced signals to balanced ones). The ratio between two working frequencies is analyzed. A novel compact microstrip crossover (letting two lines to cross each other with very high isolation) and its dual-band application is the subject of chapter 3. A dual-frequency cloak based on lumped LC-circuits is introduced in chapter 4. In chapter 5, a dual-band RF device to detect dielectric constant changes of liquids in polydimethylsiloxane (PDMS) microfluidic channels has been presented. Such a device is very sensitive, and it has significantly improved the stability. Finally, conclusion of this thesis and future works are given in chapter 6.

The baluns are the key components in balanced circuits such balanced mixers, frequency multipliers, push–pull amplifiers, and antennas. Most of these applications have become more integrated which demands the baluns to be in compact size and low cost. In this thesis, a new approach about the design of planar balun is presented where the 4-port symmetrical network with one port terminated by open circuit is first analyzed by using even- and odd-mode excitations. With full design equations, the proposed balun presents perfect balanced output and good input matching and the measurement results make a good agreement with the simulations. Second, Yagi-Uda antenna is also introduced as an entry to fully understand the quasi-Yagi antenna. Both of the antennas have the same design requirements and present the radiation properties. The arrangement of the antenna’s elements and the end-fire radiation property of the antenna have been presented. Finally, the quasi-Yagi antenna is used as an application of the balun where the proposed balun is employed to feed a quasi-Yagi antenna. The antenna is working in the S-band radio frequency and achieves a measured 36% fractional bandwidth for return loss less than -10 dB. The antenna demonstrates a good agreement between its measurement and simulation results. The impact of the parasitic director on the antenna’s performance is also investigated. The gain and the frequency range of the antenna have been reduced due to the absence of this element. This reduction presents in simulation and measurement results with very close agreement.

No description available.

<p>This thesis focuses on the design and evaluation of the meander-line antenna geometry. One standard meander-line antenna and other two non-standard meander antennas have been studied. These printed antennas are discussed with the goal of identifying which is suitable for use in a miniaturized wireless transceiver design and which is able to provide the better performance using minimal Printed Circuit Board (PCB) space. In a word, the main objective is to characterize tradeoffs and identify which antenna provides the best compromise among volume, bandwidth and efficiency.</p><p>The performance of each antenna is evaluated based on return loss, operational bandwidth, and radiation pattern characteristics. During our measurement, return loss is measured by reading the S11-port reflection coefficient on Vector Network Analyzer (VNA). This coefficient can be used to characterize how well the antenna is able to be efficiently fed. Operational bandwidth is measured as the frequency range over which the antenna keeps the value of Voltage Standing Wave Ratio (VSWR) or equivalently has -10dB return loss. Ansoft High Frequency Structure Simulator (HFSS) is used to simulate expected characteristics which are resonant frequency, bandwidth, VSWR, and radiation pattern. HFSS is used to provide a good guide for the antenna design before the actual prototype is manufactured. Simulated results are compared with results of measurement to point out the differences and help demonstrate the practical effects on antenna performance. Radiation pattern are measured to illustrate the effects of antenna miniaturization. All the above measurements are done in the anechoic chamber.</p>