Design of multi-port network utilizing microstrip-slot technique for ultra wideband system

Nowadays, there is a lot of interest on the research and development related to ultrawideband system due to the increasing demands on the applications with low power, low cost and low interference. Thus, to cope with these demands, various researches are required for the development of front-end microwave components, which include six-port network as an alternative to a mixer-based design. The configuration of a six-port network is constructed by combining coupler and power divider. In the interest to have a simple design and convenient usage to form the sixport network with ultra wideband (UWB) operation, new power divider and coupler are designed by using microstrip-slot technique. All the proposed designs are simulated via the use of CST Microwave Studio 2010 and realized using Rogers TMM4 with a conductor coating of 35 μm, thickness of 0.508 mm and dielectric constant of 4.5. The developed prototypes of the proposed designs are verified by measurement using a vector network analyser (VNA). In this thesis, a design of twosection power divideris proposed with a great UWB performance of -3.8 dB ± 0.5 dB transmission coefficient and 0º ± 2º phase difference. This power divider has bandwidth improvement of 11.9% and size reduction of 23.33% compared to the conventional design. Meanwhile, for the coupler design, a UWB coupled-line coupler with zig-zag-shaped slot that has 3 dB ± 2 dB coupling coefficient and -90º ± 5º phase difference is proposed. The proposed coupler has 109.5% bandwidth improvement with the length reduction of 20% compared to the conventional coupler. The proposed UWB coupler is then implemented into a new proposed structure of UWB 90º power divider. Then, three configurations of six-port networks formed by UWB coupler, two-section power divider and 90º power divider are designed; which are named as Type I, Type II and Type III. From the observation, Type III demonstrates the best UWB performance with magnitude imbalance of ± 5 dB and phase imbalance of ± 10° that achieving the specified UWB design goal. Furthermore, Type III has the respective size reduction of 57.16% and 34.67% compared to Type I and II. In addition, by comparing to the previous works, the proposed design has broadest bandwidth of 100% and smallest size of 50.92 mm x 35 mm. Hence, the proposed six-port network has very well UWB performance with relatively compact size and simple design, which is easy to be fabricated

Multi-Layer Ultra-Wideband Wilkinson Combiner for Arrays

This work investigates an ultra-wideband (UWB), compact, and multilayer Wilkinson power combiners for tightly coupled array (TCA) designs. The Wilkinson topology designs encompass UHF, L-, and S-bands. These combiners integrate into an experimental UWB TCA. The experimental UWB TCA divides into twenty-four columns, with each column containing eight unit cells, and each cell one-inch square. The Wilkinson power combiner contains eight input ports and one output port. Twenty-four combiners mount to the TCA’s back. The combiner condenses the two-dimensional array (8x24) to a one-dimensional or linear array (1x24). The proposed Wilkinson power combiner possesses a multilayer design reducing common mode current problems caused by vias. The Wilkinson combiner covers 500 MHz to 3.28 GHz and provides a 6.56:1 bandwidth. It achieves tight impedance matching through stripline coupling. The proposed design provides minimal phase error, equal power reception, and low power handling. The power combiner interfaces with an experimental UWB TCA antenna through SMP snap connectors. This paper examines signal combining efficiency to provide minimum path loss. This paper also examines interconnecting transmission lines traversing multiple laminate layers. This necessitates proper current handling because interconnects influence impedance, transmission, and isolation. Integrating a via picket fence improves port isolation and reduces propagating parallel plate modes. The proposed combiner design achieved the following important attributes at or better than the minimum required specifications. The measured combiner design successfully demonstrated -7.8dB minimum return loss for input and -18.1dB return loss for the outputs; 10.92dB ± 1.28dB insertion loss; -12.2db minimum isolation; ± 1.38° minimal phase error; ± 0.57dB power reception imbalance. The proposed UWB combiner design condensed the four-stage Wilkinson footprint to consume no more than 0.4in² (258mm²) surface area, weighed only 1.5oz (42.5g), and less than a half-inch thick

Impedance Transformers

Non

Microwave and Millimeter-wave Miniaturization Techniques, and Their Applications

Miniaturization is an inevitable requirement for modern microwave and mm-wave circuits and systems. With the emerging of high frequency monolithic integrated circuits, it is the passive components’ section that usually occupies the most of the area. As a result, developing creative miniaturization techniques in order to reduce the physical sizes of passive components while keep their high performance characteristics is demanding. On the other hand, it is the application that defines the importance and effectiveness of the miniaturization method. For example, in commercial handset wireless communication systems, it is the portability that primarily dictates miniaturization. However, in case of liquid sensing applications, the required volume of the sample, cost, or other parameters might impose size limitations. In this thesis, various microwave and mm-wave miniaturization methods are introduced. The methods are applied to various passive components and blocks in different applications to better study their effectiveness. Both componentlevel designs and system-level hybrid integration are benefited from the miniaturization methods introduced in this thesis. The proposed methods are also experimentally tested, and the results show promising potential for the proposed methods

Millimeter-Wave Components and Antennas for Spatial and Polarization Diversity using PRGW Technology

The evolution of the wireless communication systems to the future generation is accompanied by a huge improvement in the system performance through providing a high data rate with low latency. These systems require access to millimeter wave (mmWave) bands, which offer several advantages such as physically smaller components and much wider bandwidthcomparedtomicrowavefrequencies. However, mmWavecomponentsstillneed a significant improvement to follow the rapid variations in future technologies. Although mmWave frequencies can carry more data, they are limited in terms of their penetration capabilities and their coverage range. Moreover, these frequencies avoid deploying traditional guiding technologies such as microstrip lines due to high radiation and material losses. Hence, utilizing new guiding structure techniques such as Printed Ridge Gap Waveguide (PRGW) is essential in future mmWave systems implementation. ThemainpurposeofthisthesisistodesignmmWavecomponents,antennasubsystems and utilize both in beam switching systems. The major mmWave components addressed in this thesis are hybrid coupler, crossover, and differential power divider where the host guidingstructureisthePRGW.Inaddition,variousdesignsfordifferentialfeedingPRGW antennas and antenna arrays are presented featuring wide bandwidth and high gain in mmWave band. Moreover, the integration of both the proposed components and the featured antennas is introduced. This can be considered as a significant step toward the requirements fulfillment of today's advanced communication systems enabling both space and polarization diversity. The proposed components are designed to meet the future ever-increasing consumer experience and technical requirements such as low loss, compact size, and low-cost fabrication. This directed the presented research to have a contribution into three major parts. The first part highlights the feeding structures, where mmWave PRGW directional couplers and differential feeding power divider are designed and validated. These components are among the most important passive elements of microwave circuits used in antennabeam-switchingnetworks. Different3-dBquadraturehybridcouplersandcrossover prototypes are proposed, featured with a compact size and a wide bandwidth beyond 10 % at 30 GHz. In the second part, a beam switching network implemented using hybrid couplers is presented. The proposed beam switching network is a 4 × 4 PRGW Butler matrix that used to feed a Magneto-electric (ME) dipole antenna array. As a result, a 2-D scanning antenna array with a compact size, wide bandwidth, and high radiation efficiency larger than84%isachieved. Furthergainenhancementof5dBiisachievedthroughdeployinga hybridgainenhancementtechniqueincludingAMCmushroomshapesaroundtheantenna array with a dielectric superstrate located in the broadside direction. The proposed scanning antenna array can be considered as a step toward the desired improvement in the data rate and coverage through enabling the space diversity for the communication link. The final activity is related to the development of high-gain wide-band mmWave antenna arrays for potential use in future mmWave applications. The first proposed configuration is a differential feeding circular polarized aperture antenna array implemented with PRGW technology. Differential feeding antenna designs offer more advantages than single- ended antennas for mmWave communications as they are easy to be integrated with differential mmWave monolithic ICs that have high common-mode rejection ratio providing an immunity of the environmental noise. The proposed differential feeding antenna array is designed and fabricated, which featured with a stable high gain and a high radiation efficiency over a wide bandwidth. Another proposed configuration is a dualpolarized ME-dipole PRGW antenna array for mmWave wireless communication. Dual polarizationisconsideredoneofthemostimportantantennasolutionsthatcansavecosts and space for modern communication systems. In addition, it is an effective strategy for multiple-input and multiple-output systems that can reduce the size of multiple antennas systems by utilizing extra orthogonal polarization. The proposed dual- polarized antenna array is designed to achieve a stable gain of 15 ± 1 dBi with low cross- polarization less than -30 dB over a wide frequency range of 20 % at 30 GHz

Development of equal and unequal filtered power splitter using substrate integrated waveguide

The objective of this thesis is to investigate and provide better solution to producing filtered power splitter with compact size and with use of no resistors for its isolation. The background investigation and utilisation of the established theories build up the design equations that are adapted to power dividers. These dividers contain filtering characteristics and are employed in microstrip and substrate integrated waveguide technology. The work involves the design of a filtered power splitter with bandpass characteristics. It uses the conventional filter design synthesis to develop the design parameters that establish the coupling between the common resonator of the power splitter and the next resonator towards the output ports. An equal and an unequal division using a 5-pole, 9-square resonators is used verify this concept; this is also implemented in microstrip using Square open loop resonators (SOLR) and in SIW. Furthermore, a 3-pole 5-square resonators is also implemented in SIW; all of these operating at 2 GHz. For the equal split, the 5th order microstrip gives a bandwidth, minimum insertion loss, maximum return loss and isolation of 120MHz, 3.12dB, 15dB and 12.6dB respectively and the 3rd order SIW gives a bandwidth, minimum insertion loss, maximum return and isolation of 99Mhz, 3.57dB, 17.1dB and 6.79dB respectively; whilst the 5th order SIW gives a bandwidth, minimum insertion loss, maximum return and isolation of 140Mhz, 3.87dB, 18.3dB and 14.79dB respectively. However, it is recommended that this work can be extended to more than two output ports, to improve isolation, increase the Q factor and match the output ports

Design and Implementation of Radio Frequency Power Feeding Networks for Antenna Array Applications: Simulation and Measurements of Multiport, Equal and Unequal, Fixed and Reconfigurable Radio Frequency Power Feeding Networks for Narrow and Ultra-Wideband Applications

Power dividers are vital components and widely used in radio technology, such as antenna arrays, power amplifiers, multiplexers and mixers. A good example is the well-known Wilkinson power divider with its distinctive feeding network characteristics. A comprehensive review indicated that limited research is carried out in the area of planar multiport and reconfigurable power dividers in terms of the power levels between output ports. The main objectives of this work were to develop a small size power divider, a planer multi-output ports power divider and a power divider with a reconfigurable power division ratio. These power dividers were designed to operate over either an ultra-wideband frequency (3.1-10.6 GHz) or WLAN bands (2.4 or 5.2 GHz). A novel multi-layered topology solved the complexity of interconnecting isolation resistors by introducing an additional layer below the ground layer. The prototype was fabricated and tested to validate the results. The measurements and simulation were in good agreement. Finally, a novel uniplanar power divider with reconfigurable output power level difference was developed. The configurability feature was achieved by tuning the quarter wave transformer using one varactor diode. The power divider was applied to improve a full duplex system cancellation performance at the receiver element caused by interference from in-site transmitting antennas. This study investigated fixed power dividers, multi-output power dividers and reconfigurable power dividers. The measurements validated by the simulation results and applications proved the designed power dividers could be used in practical applications.Higher Committee for Education Development (HCED), Ira