Research And Design Of Miniaturized RF Components Based On Planar Slow-wave Transmission Lines

The development of modern communication technologies makes higher and higher requirements for the size miniaturization of radio frequency components.Planar slow-wave transmission lines,which have advantages of flexible design and easy fabrication,are widely used in the size miniaturization design of radio frequency components.And the method of size miniaturization by using planar slow-wave transmission lines has become a hot research spot for radio frequency components.In addition,making radio frequency components have harmonic suppression performance for improving the signal-to-noise ratio of communication system and communication quality has become another hot research spot.In this thesis,two kinds of microstrip planar slow-wave transmission lines and a kind of coplanar waveguide(CPW)slow-wave transmission line are designed.Then,introduction of their applications in size miniaturization and harmonic suppression of Wilkinson power divider and branch line coupler is proposed.By using folded stepped-impedance transmission lines and microstrip interdigital capacitors,a triangular slow-wave transmission line is designed.By using folded high-impedance transmission lines,parallel-plate capacitors and H-type defected ground structure,a rectangular slow-wave transmission line with defected ground is designed.By employing interdigital capacitor and meandered line,a coplanar waveguide slow-wave transmission line is designed.In the analysis sections of transmission line,we introduce the structure,size miniaturization principle,extraction of equivalent circuit parameters,design process and simulation results of the three planar slow-wave transmission lines in detail.In addition,the harmonic suppression performance of triangular slow wave transmission lines and rectangular slow-wave transmission lines with defected ground are discussed.In the application part of transmission lines,we use triangular slow-wave transmission line to design a miniaturized Wilkinson power divider and a 3dB branch line coupler with harmonic suppression.Final measured results revealed that 41.2% and 65.6% size reduction of these two components are achieved.In addition,the harmonic suppression performance of these components is verified by measured results.By employing rectangular slow-wave transmission lines with defected ground,miniaturized Wilkinson power divider and 3dB branch line coupler with harmonic suppression are designed.The final measured results demonstrate that the two designed components respectively achieve 66.8% and 76.2% size reduction and wide-20 dB range harmonic suppression.By utilizing coplanar waveguide slow-wave transmission lines,a miniaturized coplanar waveguide Wilkinson power divider is designed.Finally,the results of fabrication and measurement reveal that the designed power divider achieves 51% size reduction.