Corresponding Person: Dr' YuhJing Hwang

1
Development of Phase-Locked AMiBA Calibration
System Tzu-Chieh Hong , Yuh-Jing Hwang , Su-Wei
Chang , Tashun Wei , Wei-Ting Wong and
Yo-Sheng Lin Academia Sinica Institute of
Astronomy Astrophysics, Taipei, Taiwan,
R.O.C. Department of Electrical Engineering,
National Central University, Chung-Li, Taiwan,
R.O.C.
ASIAA
NCUEE
Introduction A final production module of the
Array of Microwave Background Anisotropy (AMiBA)
calibration system is under development in ASIAA
Receiver Laboratory. A signal source based on a
phase-locked oscillator for AMiBA calibration
system is developed. A pair of frequency standard
from the local oscillator LO central PLDRO
module are used as reference of the calibration
system. The goal of the calibration system is to
provide a low-phase-noise, stable power
millimeter-wave signal source to all the
receivers of AMiBA. The measured phase noise at
21-26GHz is around 1.2-1.5 degree, the
corresponding phase noise at 85-104GHz is around
4.8-6.0 degree. An efficient millimeter-wave
distributed network based on commercially
available HEMT single-pole-four-throw (SP4T)
Switch MMIC is also developed.
Fig. 3. Measured Power response of the comb
generator
(a) (b)
Fig. 1. System block diagram of the AMiBA
calibration source and its distribution network.
Yellow blocks represents the components of the
PLL signal source module, Blue blocks represents
the distribution network components. White blocks
represents the calibration module for each
receivers.
(c) (d) Fig. 4. Circuit module design and
fabrication efforts, (a) photograph of the
21-26GHz band-pass filter, (b) photograph of the
21-26GHz SP4T HEMT switch, (c) measured results
of the packaged 21-26GHz band-pass filter, and
(d) insertion loss of the HEMT 21-26GHz SP4T
switch .
(a)
RMS Phase Noise 0.0222 Rad (1.2721 Deg)
RMS Phase Noise 0.0258 Rad (1.4345 Deg)
(b) Fig. 5. coaxial type variable phase shifter
(a) photograph of the phase shifter with gear and
(b) measured phase delay in different tuning
states.
Fig. 2. Spectrum and phase noise measured results
of the AMiBA calibration source at 21 and 22GHz..
Corresponding Person Dr. Yuh-Jing Hwang Phone
886-2-33652200, Fax [phone] March 2008