Miniaturized lumped-element transmission line
Date Issued
2006
Date
2006
Author(s)
Lu, Chun-Yi
DOI
zh-TW
Abstract
In order to cooperate with the development of system on chip for wireless transceiver systems, the miniature Si-based lumped-element equivalent transmission line is proposed, which may achieve much wider bandwidth than the conventional T- or models of transmission lines. Based on the proposed lumped-element equivalent transmission lines, novel miniature Si-based RF/microwave passive components are also developed, so as to establish the key component technology for Si-based single chip wireless transceivers. In this thesis, we propose the implementation method of modified-T equivalent circuit of transmission line with IC process. In CMOS 0.18 process, based on the required parameters of transmission line, the symmetrical planar spiral (SPS) structure and parallel-plate capacitor are utilized to realize the circuit parameters needed in T-modified equivalent circuit. A Si-based equivalent transmission line with characterization impedance 50 Ω and electrical length of 90o at 5.25GHz is implemented using CMOS 0.18 process, and the operation bandwidth is up to 11 GHz with only 15.57 % the size of conventional designs.
The size of proposed equivalent transmission line can be further reduced by adding additional shunt capacitors at the input and output ports of a high impedance equivalent transmission-line. A Si-based quarter-wavelength equivalent transmission line resonator of 50Ω is implemented, and its size is only 14.14 % that of the conventional designs.
In order to further improve the bandwidth of proposed equivalent transmission line, the transmission line with characterization impedance of 50 Ω and electrical length of 90o at 11 GHz is implemented alternatively by a cascade of equivalent transmission line unit-cells with 2o electrical length. In this way, the self resonance frequency of the spiral inductor can be shifted to higher frequencies such that the bandwidth of equivalent transmission line becomes larger. Specifically, a lumped-element equivalent transmission line of 50Ω and 90o electrical length at 5.25GHz is implemented in CMOS 0.18 process, and a bandwidth of 20GHz is achieved.
Finally, the design of miniature Si-based Wilkinson power dividers based on the proposed lumped-element equivalent transmission line are demonstrated.
Subjects
傳輸線
慢波因子
螺旋電感
修正等效T模型
威爾金森功率分配器
transmission line
slow wave factor
cmos
spiral inductance
modified-T model
Wilkinson power divider
LTCC
Type
thesis