DocumentCode :
1553737
Title :
Low-loss analog and digital micromachined impedance tuners at the Ka-band
Author :
Kim, Hong-Teuk ; Jung, Sanghwa ; Kang, Kyungteh ; Park, Jae-Hyoung ; Kim, Yong-Kweon ; Kwon, Youngwoo
Author_Institution :
Sch. of Electr. Eng., Seoul Nat. Univ., South Korea
Volume :
49
Issue :
12
fYear :
2001
fDate :
12/1/2001 12:00:00 AM
Firstpage :
2394
Lastpage :
2400
Abstract :
Presents new types of analog and digital micromachined impedance tuners. Analog impedance tuners using resonant unit cells realized by tunable micromachined capacitors showed a wide tuning range equivalent to almost two quadrants of the Smith chart with a maximum voltage standing-wave ratio (VSWR) of 21.2 at the Ka-band. Frequency variability is also provided through the use of J-inverters with tunable capacitors. Also presented is a digital micromachined tuner, where the short-circuited shunt stubs are loaded with microelectromechanical system (MEMS) capacitive switches. The electrical length of the stub and the overall impedance of the tuner are thus controlled according to the switching states of the MEMS capacitors. The digital tuner presented impedance ranges suitable for load impedances of the RF power transistors and showed a high maximum VSWR of 32.3. Compared with the state-of-the art tuners using field-effect transistors, micromachined tuners of this paper show superior VSWR ranges as well as wide impedance ranges. Micromachined tuners are very promising for low-loss tuning of the monolithic circuits as well as for accurate noise and power characterization
Keywords :
MMIC; capacitor switching; circuit tuning; coplanar waveguide components; integrated circuit noise; micromachining; micromechanical devices; J-inverters; Ka-Band; MEMS capacitive switches; Smith chart; analog impedance tuners; coplanar waveguide; digital micromachined tuner; electrical length; load impedances; low-loss tuning; noise characterization; power characterization; resonant unit cells; short-circuited shunt stubs; switching states; tunable micromachined capacitors; voltage standing-wave ratio; Capacitors; Frequency; Impedance; Microelectromechanical systems; Micromechanical devices; Resonance; Tunable circuits and devices; Tuners; Tuning; Voltage;
fLanguage :
English
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9480
Type :
jour
DOI :
10.1109/22.971626
Filename :
971626
Link To Document :
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