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Investigation On Microwave Integrated Dielectric TM Mode Filter And Coupled-line Based Power Dividing Circuits

Posted on:2015-10-04Degree:DoctorType:Dissertation
Country:ChinaCandidate:X WangFull Text:PDF
GTID:1108330476953925Subject:Electromagnetic field and microwave technology
Abstract/Summary:PDF Full Text Request
High integration in modem wireless communication systems leads to co-existence of multi sub-systems: Global system for Mobile communications(GSM), Universal Mobile Telecommunications System(UMTS) and Long Term Evolution. It puts forward higher requirements for devices in each system on miniaturization, high performance, multifunction and low cost. Meanwhile, for sharing the resources, and reducing system complicity, more and more dual-band or even multiple-band RF and microwave sub-systems have been brought to our attention. Thus,the demand on novel and high performance devices becomes stronger and stronger. In this paper, based on varies of passive devices in wireless communication systems, including two-port, three-port, and four-port devices, we utilize new design concept and new structures to realize these devices with high performance and miniaturized size.The main academic contributions of this dissertation are as follows.(1) Monoblock dielectric is utilized to design filters. Conventional metal cavity based resonator is replaced by metalized monoblock dielectric resonator, which saves the space that is occupied by metal walls. It not only reduces the size and weight of the resonators, but also increase the space utilization that leads to increasing of the Q factor. Since the mid dielectric rod does not need any extra fixture, stability is guaranteed and extra loss will not be introduced. Meanwhile, the thermal stability is excellent.(2) For the advantages of the monoblock dielectric filters we mentioned above, we utilize this structure to be surface mounted on PCB. By introducing tuning structures that soldered on the metalized dielectric and though the via holes on the dielectric, the monoblock filter can be tuned in certain range. And by introducing microstrip on PCB, electrical coupling can be realized between two resonators to realize controllable transmission zeros.(3) For the first time, we proposed a dual-band coupler based on coupled-line coupler, and the analytical design equations are derived from- iv-even- and odd-mod analysis. The major advantages of the coupler include: 1) large range of frequency ratio; 2) coupling coefficients only depend on the coupling of the coupled-line which means very high impedance or very low impedance that cannot be realized can be avoid in realizing arbitrary coupling coefficients; 3) wider bandwidth than branch-line coupler; 4) compact size and small occupation.(4) A dual-band and wide-band tandem coupler is proposed. The structure is very compact which only contains two pairs of coupled-line and a single transmission line. Analytical design equations are derived from even- and odd-mod analysis. By properly design the frequency ratio of the two designated frequency, wide-band performance can be obtained. The measured results show that over 90% fractional bandwidth can be realized.(5) A novel Gysel power divider is proposed. By introducing a pair of a quarter-wavelength coupled-line with grounded resistors, the size of the power divider can be highly reduced as compare to conventional Gysel power divider. And,it only needs one grounded resistor when the power division is unequal. Thus, the structure is simplified and the demand on resistor is reduced.(6) Compact baluns are proposed based on coupled-line balun, including the one with grounded structures and the one without grounded structures. The one with grounded structures presents wide-band performance, and the other one reduce the manufacturing complicity and cost since it does not need any grounded structures as compare to conventional coupled-line balun. Both of these baluns is very compact for they only consist of one pair of coupled-line and a single transmission line.
Keywords/Search Tags:Passive device, multi-port, filter, coupler, power divider, balun, monoblcok dielectric filter, surface mount, high quality factor, dual-band, wide-band, arbitrary coupling coefficient, coupled-line
PDF Full Text Request
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