The Design Of Balanced Power Distributing Devices

Balanced circuits and systems have drawn much attention due to their high immunity to the environmental noise and electromagnetic(EM)interferences,and the research of active balanced circuits have got rapid development with the development of chip technology.However,the research of passive balanced circuits,especially the balanced power distributing devices,are relatively slow.Meanwhile,the RF front-end circuits are required to have high integration and small size under the trend of high-integration and miniaturized wireless terminals and systems.For the demand of these two aspects,we have a full investigation of the domestic and overseas reach status for the balanced power distributing devices.The novel balanced power distributing devices will be carried out,where improved performance and compact size can be achieved.Furthermore,the fusion design with multi functions will be proposed,which can further compact the size of RF front-end circuits and improve the performance of the whole system.In this thesis,full balanced power divider is proposed as well as the design theory,which can realize the basic function of differential-mode power division and common-mode suppression.Based on this,balanced power divider realized by coupled microstrip lines,balanced power divider based on back-to-back Wilkinson power dividers and dual-band balanced power divider based on T-junction structures are proposed,respectively.For the balanced power divider realized by coupled microstrip lines,it shows the advantages of compact size,easy conection with other balanced devices and in-phase or out-of-phase output ports.For the balanced power divider based on back-to-back Wilkinson power dividers,it shows wide bandwidth with good common-mode suppression.And for the dual-band balanced powe divider based on T-junction structure,it works on two frequency bands with good out-of-band suppression,which can fill the blank of this kind of design.Then,full balanced hybrid is proposed,which theoretical basis is provided and basic function is achieved.Based on this,balanced 90° hybrid realized by coupled microstrip lines,balanced 90° hybrid built in Low Temperature Co-fired Ceramic(LTCC)and balanced 180° hybrid with arbitrary power division ratio are proposed,respectively.For the balanced 90° hybrid realized by coupled microstrip lines,it shows the advantage of easy connection of other balanced devices with specific theoretical analysis,which can fill the blank of the balanced 90° hybrid.For the balanced 90° hybrid built in LTCC,the circuit size is further reduced,which shows the ability for practical application.And for the balanced 180° hybrid with arbitrary power division,it shows the function of arbitrary power division and the theoretical basis of the design is proposed,which shows the actual guiding significance.Meanwhile,the power dividers with both balanced and single-ended ports are proposed as well as their basic function,theoretical analysis and application.Based on this,single-ended-to-balanced power divider,out-of-phase balanced-to-single-ended power divider,in-phase balanced-to-single-ended power divider with arbitrary power division,1 to 2 balanced power divider based on out-of-phase balanced-to-single-ended power divider and 1 to 2n balanced power divider based on out-of-phase balanced-to-single-ended power divider and single-ended-to-balanced power dividers are proposd,respectively.For the single-ended-to-balanced and out-of-phase balanced-to-single-ended power dividers,they both show the advantage of easy connection with both balanced and single-ended devices and good common-moder suppression,which can fill the blank of these two kinds of design.For the in-phase balanced-to-single-ended power divider with arbitrary power division,it shows the advantages of low insertion loss,compact size,in-phase balanced-to-single-ended conversion and high power division ratio.For the 1 to 2 balanced power divider based on out-of-phase balanced-to-single-ended power divider,it shows the advantages of simple structure,compact size and easy fabraction.And for the 1 to 2n balanced power divider based on out-of-phase balanced-to-single-ended power divider and single-ended-to-balanced power dividers,the advantage is that it not only compact the size and reduce the cost when comparing with the approach using all 1 to 2 way balanced power dividers but also ensure the function of differential-mode power dividing and common-mode suppression.Lastly,balanced power divider fused with filtering function is explored,which can not only realize the function of differential-mode power division but also the filtering performance.Based on this,a balanced-to-single-ended filtering power divider is designed,which can reduce the number of the devices and the size,improve the performance,and finally realize the effect of 1+1 > 2.And the design procedure and theoretical analysis of the fusion design are proposed,which can fill the blank of this kind of design.To conclude,the proposed balanced power distributing devices in this thesis provide theoretical and application foundation for the development of the balanced RF front-end circuits.