Two compact planar crossed-dipole antennas loaded with near-field resonant parasitic (NFRP) elements are reported. The NFRP and crossed-dipole elements are designed for the desired circularly polarized (CP) radiation. By placing the NFRP element over the driven element at angles of 0 degrees and 45 degrees, respectively, dual-band and broadband CP antennas are realized. All radiating elements of antennas are 35 mm x 35 mm x 0.508 mm (0.187 lambda(0) x 0.187 lambda(0) x 0.0027 lambda(0) at 1.6 GHz) in size. The dual-band CP antenna has a measured vertical bar S-11 vertical bar < -10-dB bandwidth of 226 MHz (1.473-1.699 GHz) and measured 3-dB axial ratio (AR) bandwidths of 12 MHz (1.530-1.542 GHz) and 35 MHz (1.580-1.615 GHz) with minimum AR CP frequencies of 1.535 GHz (AR = 0.26 dB) and 1.595 GHz (AR = 2.08 dB), respectively. The broadband CP antenna has a measured vertical bar S-11 vertical bar< -10-dB bandwidth of 218 MHz (1.491-1.709 GHz) and a 3-dB AR bandwidth of 145 MHz (1.490-1.635 GHz). These compact antennas yield bidirectional electromagnetic fields with high radiation efficiency across their operational bandwidths.

This dissertation presents a new technique for miniaturization of printed RF circuits and antennas. The technique is based on lumped circuit elements and volumetric reactive pin loadings. The vertical arrangement of the pins is shown to provide a meandered current path within the device volume enhancing the miniaturization achieved with sole application of lumped circuit components. The technique is applied for antenna and filter size reduction. In antenna applications, it is shown that due to the presence of the reactive pin loading the overall size of a printed antenna can be miniaturized without affecting the radiation efficiency performance. One of the major advantages of this approach over the existing miniaturization techniques is that it allows reducing the overall size of the antenna (i.e. the substrate size) in addition to its metallization footprint area. Specifically, three antenna designs are presented for GPS and ISM applications. Firstly, a miniaturized wide-band CDL antenna has been introduced. The antenna consists of two loops which are loaded with lumped inductors and coupling capacitors. The design is shown to exhibits 49% smaller footprint size as compared to a traditional patch antenna without degrading the bandwidth performance. Secondly, a circular polarized compact dual-band CDL GPS antenna loaded with lumped capacitors and vertical pins is shown. The antenna operates with >50% lesser area as compared to a traditional L2 patch antenna without degrading its radiation performance. Thirdly, a patch antenna with its cavity loaded with CSRRs is presented. The novelty of the design is that it provides circularly symmetric arrangement of CSRRs thereby enabling the antenna to exhibit circular polarization (CP). Apart from CSRR, further size reduction is obtained by simultaneously reducing the substrate size and ground plane metallization around the CSRRs and loading it with pins. The antenna is 44% smaller than a traditional patch antenna without causing degradation in the antenna's radiation efficiency performance. To extend the volumetric loading to filter applications, the last chapter of the dissertation presents a detailed analysis to understand how geometrical factors (e.g. periodicity, radius, width of the host transmission line, etc) affect the miniaturization performance and quality factor. As a design example, a 2GHz pin loaded hairline filter with 17% -3dB |S21| bandwidth and 1.5dB insertion loss is demonstrated. The footprint size of the filter is ~λ0/16×λ0/9 @ 2GHz and is 45% smaller than its traditional counterpart.

At the moment Swedish Transport Administration uses a monitor system that candetect urgent errors as warm ball-bearings and flat wheels etc. with stationarydetectors. To avoid these errors Swedish Transport Administration, UPWIS AB andUppsala University work with a system that will continuously monitoring the train todetect the errors as fast as possible. This will save money in the future for SwedishTransport Administration and all other partners that use the rails.Swedish Transport Administration has already RFID readers beside the rail to detecttrains position. The new monitoring system will use these readers and send data fromthe monitoring system via these readers to a database.The aim of this thesis work is to design and build a RFID antenna to send data fromthe monitoring system to the RFID readers. The antenna should be a circularpolarized and it needs to manage the harsh environment on the train.This thesis work started with a theoretical study which investigated four commonantenna types (dipole, loop, PIFA and patch/microstrip) to evaluate which antennatype that is the best solution for this application. It was decided to design a patchantenna from the theoretical study since it fulfils all the requirements for the antenna.Simulations and tests shows that the antenna is circular polarized and have amaximum reading distance of 5 m for 868 MHz. For 2.45 GHz it is linear polarizedand has a reading distance of at least 10 m. With other hardware settings the antennawill have longer reading distance at 2.45 GHz.When all parts of the test bed was finished the test bed was mounted on themeasurement wagon. The final test shows that the antenna fulfils the task. Theantenna transmitted the data from the sensor boxes to the RFID readers.The report suggests future work to minimize the reading distance and size for theantenna. These are: transfer sensor data to RFID tag by “multi hop”, hardwareimprovement for instance antenna diversity and using another substrate (higherdielectric constant).

In wireless communication systems, multiple standards have been implemented to meet the past and present demands of different applications. This proliferation of wireless standards, operating over multiple frequency bands, has increased the demand for radio frequency (RF) components, and consequently power amplifiers (PA) to operate over multiple frequency bands. In this research work, a systematic approach for the synthesis of a novel dual-band matching network is proposed and applied for effective design of PA capable of maintaining high power efficiency at two arbitrary widely spaced frequencies. The proposed dual-band matching network incorporates two different stages. The first one aims at transforming the targeted two complex impedances, at the two operating frequencies, to a real one. The second stage is a dual-band filter that ensures the matching of the former real impedance to the termination impedance to 50 Ohm. Furthermore, an additional transmission line is incorporated between the two previously mentioned stages to adjust the impedances at the second and third harmonics without altering the impedances seen at the fundamental frequencies. Although simple, the harmonic termination control is very effective in enhancing the efficiency of RF transistors, especially when exploiting the Class J design space. The proposed dual-band matching network synthesis methodology was applied to design a dual-band power amplifier using a packaged 45 W gallium nitride (GaN) transistor. The power amplifier prototype maintained a peak power efficiency of about 68% at the two operating frequencies, namely 800 MHz and 1.9 GHz. In addition, a Volterra based digital predistortion technique has been successfully applied to linearize the PA response around the two operating frequencies. In fact, when driven with multi-carrier wideband code division multiple access (WCDMA) and long term evolution (LTE) signals, the linearized amplifier maintained an adjacent channel power ratio (ACPR) of about 50 dBc and 46 dBc, respectively.

This dissertation divides into three parts: (a) design and research of asymmetric stepped impedance resonator (SIR); (b) design and fabrication of dual-band and ultra-wide band (UWB) bandpass filters (BPFs) and (c) design and fabrication of millimeter wave filters. (a)design and research of asymmetric stepped impedance resonator. In the first part of the dissertation, we propose an asymmetric SIR, and the effect of electrical length ratio and impedance ratio on the performance of frequency has been discussed in detail. The insertion loss and spurious can be controlled by the structural parameters of asymmetric SIR which decreases the length of resonator effectively and achieves the reduction of whole size. Additionally, this characterization of the asymmetric SIR can be extensively applied on the interconnection of RFIC. (b) design and fabrication of dual-band and ultra-wide band (UWB) filters. In the second part of the dissertation, we propose dual-band and UWB BPFs by using asymmetric SIRs. The designed dual-band BPF is conformed to the standard of wireless local area network (WLAN), and the designed UWB BPF is conformed to the standard that Federal Communications Commission (FCC) defined. The structural parameters of asymmetric SIR can be adjusted accurately by the theoretical equations we calculated. Then, the ideal performance can be achieved. (c) design and fabrication of millimeter wave filters. In the third part of the dissertation, we propose the design of millimeter wave filters fabricated by the standard of complementary metal-oxide semiconductor (CMOS). Asymmetric SIRs are used to design the microwave filter to estimate that the feasibility of system on chip (SoC). Finally, some suggestions are made in the future work on technology for system on chip (SoC).

This dissertation aims to design and implement wireless passive components using domestic integrated passive device (IPD) technology. The research focuses on exploiting novel 3-D structures for various kinds of IPD-based wireless passive components including high-quality and high-efficiency planar transformers, baluns, filters, and combiners to achieve miniature size and high performance. A physical model has been developed for modeling the planar transformers. In this dissertation, a scalable transformer model in integrated passive device technology is further used to correlate with the coupled-line sections of a conventional Marchand balun. This improves the efficiency of the design of planar transformers with equivalent coupled-line parameters such as the coupling factor, and even- and odd-mode characteristic impedances and quality factors. Additionally, the proposed model-based design approach provides effective optimization techniques that incorporate geometrical and material parameters. In addition, a compact transformer-based coupled balun bandpass filter design is proposed based on integrated circuit technology and the equivalent circuit is established. Using a planar transformer with high-density fully symmetrical wiring not only greatly reduces the component size but also provides a superior stopband rejection and selectivity. Finally, by using the spiral-shaped resonators, the dual-band third-order bandpass filter has been implemented on organic substrates. The proposed BPF design is verified to overcome the elements¡¦ parasitic effects, and thus can be miniaturized and optimized with high degree of freedom. The simulation and measurement results have good agreement for the proposed design in this dissertation.

In the past decade, artificial materials have attracted considerable attention as potential solutions to meet the demands of modern microwave technology for simultaneously achieving component minimization and higher performance in mobile communications, medical, and optoelectronics applications. To realize this potential, more research on metamaterials is needed. In this dissertation, new bandpass filter and diplexer as microwave metamaterial applications have been developed. Unlike the conventional complementary split ring (CSRR) filters, coupled lines are used to provide larger coupling capacitance, resulting in better bandpass characteristics with two CSRRs only. The modified bandpass filters are used to deisgn a compact diplexer. A new CSRR antenna fed by coplanar waveguide has also been developed as another metamaterial application. The rectangular shape CSRRs antenna achieves dual band frequency properties without any special matching network. The higher resonant frequency is dominantly determined by the outer slot ring, while the lower resonant frequency is generated by the coupling between two CSRRs. The proposed antenna achieves about 35 percent size reduction, compared with the conventional slot antennas at the low resonant frequencies. As a future alternative energy solution, space solar power transmission and wireless power transmission have received much attention. The design of efficient rectifying antennas called rectennas is very critical in the wireless power transmission system. The conventional method to obtain long distance range and high output power is to use a large antenna array in rectenna design. However, the use of array antennas has several problems: the relatively high loss of the array feed networks, difficultiy in feeding network design, and antenna radiator coupling that degrades rectenna array performance. In this dissertation, to overcome the above problems, a reflectarray is used to build a rectenna system. The spatial feeding method of the reflectarray eliminates the energy loss and design complexity of a feeding network. A high gain rectifying antenna has been developed and located at the focal point of the reflectarray to receive the reflected RF singals and genterate DC power. The technologies are very useful for high power wireless power transmission applications.

This paper proposes novel PIFA and monopole designs for dual-band or multi-band wireless communications, especially for mobile phones and CF (compact flash) card. The dual-frequency designs for mobile phone mainly utilize one or more metal branch strips to excite two resonant modes. By tuning the dimensions of branch strips, the ratio of the antenna¡¦s first two resonant frequencies can be achieved to be about 2.0, which makes it very promising for 900/1800 MHz operations. In addition, the broadband and quad-band (AMPS/GSM/DCS/PCS) designs for mobile phone application are also proposed. The broadband antenna design, unlike the above-mentioned dual-frequency designs for operating at two separate resonant modes, is more suitable to cover several nearby communication bands (DCS/PCS/UMTS/WLAN 2.45 GHz). The quad-band antenna design utilizes a £k-shape matching bridge to achieve a wider bandwidth both in lower and higher bands. For CF Card application, the triangular chip antenna having one longer and one shorter strip lines can generate the lower and higher modes covering the WLAN 2.4 and WLAN 5.2/5.8 GHz bands. All the antenna designs proposed are very promising to be concealed within the housing of the mobile phones or CF card.

This dissertation presents four dual-band printed monopole antennas. There are three printed monopole antennas operating in 2.4 GHz and 5.2/5.8 GHz WLAN bands, and a dual wideband printed monopole operating applies in 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands. The proposed antennas mainly use two approaches to achieve dual-band and dual wideband operations. The first method uses two different resonant paths in radiating monopole to excite two desired operating frequencies. The proposed configuration using the first method is a printed G-shaped monopole antenna. The second method places the conductor-backed plane on the other side of the radiated monopole to perturb its resonant behaviors for enhancing impedance bandwidth. Three configurations using the second method are proposed. The one with the best wideband performance is a printed rectangular monopole antenna with a trapezoid conductor-backed plane. Measured results for the proposed antennas show satisfactory performances and good agreement with the simulated results.

Quantum Well Infrared Photodetectors (QWIPs) are strong competitors to other detector technologies for future third generation thermal imagers. QWIPs have inherent advantages of mature III-V material system and well settled fabrication technology, as well as narrow band photo-response which is an important property facilitating the development of dual-band imagers with low crosstalk. This thesis focuses on the development of long/mid wavelength dual band QWIP focal plane arrays (FPAs) based on the AlGaAs/GaAs material system. Apart from traditional single band QWIPs, the dual-band operation is achieved by proper design of a bias tunable quantum well structure which has two responsivity peaks at 4.8 and 8.4 um for midwave infrared (MWIR) and longwave infrared (LWIR) atmospheric windows, respectively. The fabricated large format (640x512) FPA has MWIR and LWIR cut-off wavelengths of 5.1 and 8.9 um, and it provides noise equivalent temperature differences (NETDs) of ~ 20 and 32 mK (f/1.5 at 65 K) in these bands, respectively. The employed bias tuning approach for the dual-band operation requires the same fabrication steps established for single band QWIP FPAs, which is an important advantage of the selected method resulting in high-yield, high-uniformity and low-cost. Results are encouraging for fabrication of low cost, large format, and high performance dual band FPAs, making QWIP a stronger candidate in the competition for third generation thermal imagers