This is to report on our progress and current status of the Sub-Millimeter Array (SMA) project in... more This is to report on our progress and current status of the Sub-Millimeter Array (SMA) project in Taiwan. In particular, we will describe the development of the SMA receiver systems. The SMA is the first major instrumentation project in the Taiwanese astronomical research community. The primary design and development of the SMA receiver system has been carried out in the receiver laboratory at the Smithsonian Astrophysical Observatory (SAO). We have undertaken the system assembly, integration and testing, and the task to fabricate the superconductor-insulator-superconductor (SIS) mixers used for our SMA receivers. The system will be initially equipped with two SIS receiver modules to cover 176-256 GHz and 250-350 GHz bands, followed with a third band of 600-720 GHz. The receiver system will be installed in the antenna in the mid-2000. The major milestone for this project is to ship the antennas to Mauna Kea, Hawaii to join the rest of the SMA for testing interferometric observation before the end of the year 2000.
IEEE Antennas and Propagation Society International Symposium. Transmitting Waves of Progress to the Next Millennium. 2000 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.00CH37118), 2000
The three-antenna method is a well-known technique to measure the antenna gain without using a re... more The three-antenna method is a well-known technique to measure the antenna gain without using a reference antenna. However, it operates in a transmission-type arrangement, a long return cable is then required. Several methods were developed to eliminate the return cable by using the radar cross section (RCS) measurement approach. We propose a quasi-monostatic arrangement that will greatly improve the measurement sensitivity. Three antennas are arranged as transmitting, receiving and reflecting antennas as shown, which is represented as a three-port network. By measuring the two-port scattering parameters at the reference planes of transmitting and receiving antennas while the reflecting antenna is terminated with three different terminators, the three-port scattering parameters can be calculated. One can then follow the three-antenna method to find the gain of each antenna. In addition, the structural scattering characteristics of each antenna can be solved
IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229), 2001
2007 IEEE Antennas and Propagation International Symposium, 2007
Focusing on characterizing fully symmetric four-port devices using a two-port vector network anal... more Focusing on characterizing fully symmetric four-port devices using a two-port vector network analyzer (VNA), the authors formulate a new method of measurement in this paper. The device under test (DUT), is embedded in two probe pads and two auxiliary terminations for one to perform on-board measurement using two ground-signal-ground (GSG) probes and a two-port VNA. The DUT is a 30 GHz substrate integrated waveguide (SIW) Riblet short-slot hybrid with microstrip-to-waveguide transitions, and is fabricated on Rogers RO4003 reg substrate with 8 mil thickness. By taking advantage of the thru-reflection-line (TRL) calibration technique and the new method, the four-port scattering matrix (S-matrix) of DUT is reconstructed.
2007 IEEE Antennas and Propagation International Symposium, 2007
In this paper, an antenna array using an oscillator array with coupled type-II PLLs is proposed. ... more In this paper, an antenna array using an oscillator array with coupled type-II PLLs is proposed. With type-II PLLs, applying only one control voltage to the one end PLL can give the oscillators to precisely have their signals with the desired phase distribution to the radiating elements for beam-steering applications. Switching the output signal of the phase detector (PD) of the middle element in the array to either a non-inverting buffer amplifier or an inverting one, the sum or difference pattern can be achieved. Furthermore, the antenna array operates stably at the frequency of the reference signal.
2008 IEEE Antennas and Propagation Society International Symposium, 2008
This paper presents an ESA with beam-switching capability. Using a type-II CPLLA and a reference ... more This paper presents an ESA with beam-switching capability. Using a type-II CPLLA and a reference signal, this EAS steers its pattern by a DC control voltage, reduces the beam-pointing error arising from phase errors, and holds its operating frequency stably at the reference frequency. By one switch and two buffer amplifiers, it switches its pattern between the sum and difference patterns. Utilizing prescalers, its beam-scanning range is significantly extended. Thus, it has the potential for target tracking applications.
IEEE MTT-S International Microwave Symposium Digest, 2003, 2003
The push-push oscillator is commonly used for implementing a second-harmonic oscillator. By combi... more The push-push oscillator is commonly used for implementing a second-harmonic oscillator. By combining two out-of-phase oscillators, their fundamental frequency components are canceled and the second-harmonic components are enhanced. This structure can be extended to triple-push, quadruple-push and hence N-push harmonic oscillators. From the oscillator injection-locking phenomenon, the relative phase between coupled oscillators can be controlled by the oscillator free-running frequency.
IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229), 2001
A novel approach is developed and tested for achieving phase conjugation. Using anti-symmetric pa... more A novel approach is developed and tested for achieving phase conjugation. Using anti-symmetric pair of subharmonically injection locked selfoscillating mixers (SILSOM), which oscillate at ω, an input signal at ω/2 will be converted to its conjugated signal. No external RF source is needed for LO pumping, and the input and output signals will be the same frequency due to the
This paper presents the designs and measurement results of several K-band monolithic microwave in... more This paper presents the designs and measurement results of several K-band monolithic microwave integrated circuits (MMIC) including 21-26 GHz amplifiers and 2-25 GHz distributed amplifiers. The MMIC chips are fabricated with a 0.2-µm gate-length pseudomorphic (PM) GaAs-based HEMT MMIC technology, carried out by commercially available foundry.
This is to report on our progress and current status of the Sub-Millimeter Array (SMA) project in... more This is to report on our progress and current status of the Sub-Millimeter Array (SMA) project in Taiwan. In particular, we will describe the development of the SMA receiver systems. The SMA is the first major instrumentation project in the Taiwanese astronomical research community. The primary design and development of the SMA receiver system has been carried out in the receiver laboratory at the Smithsonian Astrophysical Observatory (SAO). We have undertaken the system assembly, integration and testing, and the task to fabricate the superconductor-insulator-superconductor (SIS) mixers used for our SMA receivers. The system will be initially equipped with two SIS receiver modules to cover 176-256 GHz and 250-350 GHz bands, followed with a third band of 600-720 GHz. The receiver system will be installed in the antenna in the mid-2000. The major milestone for this project is to ship the antennas to Mauna Kea, Hawaii to join the rest of the SMA for testing interferometric observation before the end of the year 2000.
IEEE Antennas and Propagation Society International Symposium. Transmitting Waves of Progress to the Next Millennium. 2000 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.00CH37118), 2000
The three-antenna method is a well-known technique to measure the antenna gain without using a re... more The three-antenna method is a well-known technique to measure the antenna gain without using a reference antenna. However, it operates in a transmission-type arrangement, a long return cable is then required. Several methods were developed to eliminate the return cable by using the radar cross section (RCS) measurement approach. We propose a quasi-monostatic arrangement that will greatly improve the measurement sensitivity. Three antennas are arranged as transmitting, receiving and reflecting antennas as shown, which is represented as a three-port network. By measuring the two-port scattering parameters at the reference planes of transmitting and receiving antennas while the reflecting antenna is terminated with three different terminators, the three-port scattering parameters can be calculated. One can then follow the three-antenna method to find the gain of each antenna. In addition, the structural scattering characteristics of each antenna can be solved
IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229), 2001
2007 IEEE Antennas and Propagation International Symposium, 2007
Focusing on characterizing fully symmetric four-port devices using a two-port vector network anal... more Focusing on characterizing fully symmetric four-port devices using a two-port vector network analyzer (VNA), the authors formulate a new method of measurement in this paper. The device under test (DUT), is embedded in two probe pads and two auxiliary terminations for one to perform on-board measurement using two ground-signal-ground (GSG) probes and a two-port VNA. The DUT is a 30 GHz substrate integrated waveguide (SIW) Riblet short-slot hybrid with microstrip-to-waveguide transitions, and is fabricated on Rogers RO4003 reg substrate with 8 mil thickness. By taking advantage of the thru-reflection-line (TRL) calibration technique and the new method, the four-port scattering matrix (S-matrix) of DUT is reconstructed.
2007 IEEE Antennas and Propagation International Symposium, 2007
In this paper, an antenna array using an oscillator array with coupled type-II PLLs is proposed. ... more In this paper, an antenna array using an oscillator array with coupled type-II PLLs is proposed. With type-II PLLs, applying only one control voltage to the one end PLL can give the oscillators to precisely have their signals with the desired phase distribution to the radiating elements for beam-steering applications. Switching the output signal of the phase detector (PD) of the middle element in the array to either a non-inverting buffer amplifier or an inverting one, the sum or difference pattern can be achieved. Furthermore, the antenna array operates stably at the frequency of the reference signal.
2008 IEEE Antennas and Propagation Society International Symposium, 2008
This paper presents an ESA with beam-switching capability. Using a type-II CPLLA and a reference ... more This paper presents an ESA with beam-switching capability. Using a type-II CPLLA and a reference signal, this EAS steers its pattern by a DC control voltage, reduces the beam-pointing error arising from phase errors, and holds its operating frequency stably at the reference frequency. By one switch and two buffer amplifiers, it switches its pattern between the sum and difference patterns. Utilizing prescalers, its beam-scanning range is significantly extended. Thus, it has the potential for target tracking applications.
IEEE MTT-S International Microwave Symposium Digest, 2003, 2003
The push-push oscillator is commonly used for implementing a second-harmonic oscillator. By combi... more The push-push oscillator is commonly used for implementing a second-harmonic oscillator. By combining two out-of-phase oscillators, their fundamental frequency components are canceled and the second-harmonic components are enhanced. This structure can be extended to triple-push, quadruple-push and hence N-push harmonic oscillators. From the oscillator injection-locking phenomenon, the relative phase between coupled oscillators can be controlled by the oscillator free-running frequency.
IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229), 2001
A novel approach is developed and tested for achieving phase conjugation. Using anti-symmetric pa... more A novel approach is developed and tested for achieving phase conjugation. Using anti-symmetric pair of subharmonically injection locked selfoscillating mixers (SILSOM), which oscillate at ω, an input signal at ω/2 will be converted to its conjugated signal. No external RF source is needed for LO pumping, and the input and output signals will be the same frequency due to the
This paper presents the designs and measurement results of several K-band monolithic microwave in... more This paper presents the designs and measurement results of several K-band monolithic microwave integrated circuits (MMIC) including 21-26 GHz amplifiers and 2-25 GHz distributed amplifiers. The MMIC chips are fabricated with a 0.2-µm gate-length pseudomorphic (PM) GaAs-based HEMT MMIC technology, carried out by commercially available foundry.
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Papers by Tah-hsiung Chu