• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.371-379
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• 2002

In this paper, the MMIC SPST switches operating from DC to 3GHz were designed and implemented. Prior to the design of switches, the small and large-signal switch models were needed to predict switch performance accurately. The newly proposed small-signal switch model parameters were extracted from measured S-parameters using optimization technique with estimated initial values and boundary limits. In the extraction of large-signal switch model parameters, the current source was modeled by fitting empirical equations to measured DC data and the charge model was derived from extracted channel capacitances from measured S-parameters varying the drain-source voltage. To design basic series-shunt SPST switches and isolation-improved SPST switches, we applied this model to commercial microwave circuit simulator. The improved SPST switches exhibited 0.302dB insertion loss, 35.762dB isolation, 1.249 input VSWR, 1.254 output VSWR, and about 15.7dBm PldB with 0/-3V control voltages at 3GHz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.352-355
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• 2002

본 논문에서는 series-shunt type의 PIN diode를 사용하여 8 ㎓ (7.7㎓ - 8.3㎓) 에서 사용 가능한 switch를 설계 제작하였다 스위치의 중요한 사양인 격리도 (-50㏈ 미만) 삽입손실(-1.5㏈ 미만) 입력전력 허용치 (평균전력 0.5 watt 이상 ) 입출력 정재파비 (1.3:1) 등을 고려하여 설계하였으며, 제작은 인텍웨이브사의 알루미나 기판을 이용한 thin film 공정을 이용하였으며, 측정 또한 이 네 가지에 중점을 두었다. 격리도는 중심 주파수 근방에서 비교적 넓은 대역을 가지고 -50㏈ 미만이었으며, 삽입손실은 -1.3㏈-1.6㏈였다. 입출력 정재파비는 1 -1.4였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2A
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• pp.201-206
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• 2006

A SPST Switch MMIC which used for Microwave Switch Matrix(MSM) of communications satellite payload with multi-beam function has been designed and fabricated. New RE FET switch configuration has been devised to improve power characteristics and isolation. Input and output return losses are better than another switches reported previously for both On and Off states. The MMIC chips were fabricated in 0.15um GaAs pHEMT process and measured insertion loss less than 2.0dB and isolation more than 63dB in the frequency range of 3GHz$\∼$4GHz. Output 3rd order interceptpoint above 32dBm has been recorded and the value is very high even though the unit pHEMT has gate width of 0.2mm and only four pHEMT are used in the MMTC.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.111-114
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• 2005

The isolation performance of the S-band single-pole single-throw (SPST) monolithic microwave integrated circuit (MMIC) switch with two different RF-interconnection approaches, microstrip and grounded coplanar waveguide (GCPW) lines, are investigated. On-to-off isolation is improved by 5.8 dB with the GCPW design compared with the microstrip design and additional improvement of 6.9dB is obtained with the coplanar wire-bond interconnection (CWBI) at 3.4 GHz. The measured insertion loss and third-order inter-modulation distortion (IMD3) are less than 2.43 dB over 2.5 CHz $\sim$ 4 GHz and greater than 64 dBc.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.134-138
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• 2006

The isolation performance of the S-band single-pole single-throw(SPST) monolithic microwave integrated circuit (MMIC) switch with two different RF-interconnection approaches, microstrip and grounded coplanar waveguide(GCPW) lines, are investigated. On-to-off isolation is improved by 5.8 dB with the GCPW design compared with the microstrip design and additional improvement of 6.9 dB is obtained with the coplanar wire-bond interconnection(CWBI) at a 3.4 GHz. The measured insertion loss and third-order inter-modulation distortion(IMD3) are less than 1.94 dB over $3.2{\sim}3.6\;GHz$ and greater than 64 dBc.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.10 s.101
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• pp.989-994
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• 2005

A MMIC(Monolithic Microwave Integrated Circuit) switch chip using InGaAs/GaAs p-HEMT process has been designed for MSM(Microwave Switch Matrix) of satellite communication system. An absorptive type MMIC switch is adopted for good reflection coefficients performances of input and output ports at both on and off states. And, a quarter wavelength impedance transformer is realized with lumped elements of MIM capacitor and spiral inductor for 3 GHz band to reduce the chip size. This MMIC switch covers the frequency range of $3.2\~3.6\;GHz$. According to the on-wafer measurement, the fabricated MMIC switch with miniature size of $1.6\;mm{\times}1.3\;mm$ demonstrates insertion loss below 2 dB and isolation above 56.8 dB, and the performance coincides with simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1A
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• pp.58-64
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• 2006

A 900-MHz band transceiver has been developed for RFID reader applications. In the transmitter, a GaAs SPST switch is used for high speed switching and low power consumption. In the receiver, a double balanced mixer is used to compress even-harmonic products. The ASK demodulator which consists of an active filter and comparator is used to reject the unwanted in band interferers. The transceiver produces a maximum transmitting power of 30 dBm and exhibits an 5 m communication range with a 6-dBi gain antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.992-999
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• 2008

This paper describes the design of SPST PIN diode switch which has a 2 kW high power handling capability within $50{\mu}s$ switching speed in $20{\sim}100$ MHz VHF-band. Design factors were investigated and it was confirmed by simulation that the characteristics of insertion loss, VSWR, and isolation met design goal. Also, the capability to handle 2 kW high power with maximum fast switching speed less than $20{\mu}s$ was confirmed and insertion loss less than 0.2 dB, VSWR less than 1.17:1, and isolation higher than 40 dB were obtained by experiments.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2233-2235
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• 2000

We present the characteristics of microwave and mechanical behavior for the electrostatically actuated z-shaped laterally driven micriomachined CPW SPST(Single Pole Single Throw) Switch, which is for the application of the microwave communication systems. In this paper, we have aimed to maintain advantages. such as low insertion loss and low power consumption that the previously developed RF MEMS Switch has and minimize also stiction problem. enhance the microwave characteristics by etching of substrate beneath the switch, realize the pull-in voltage of below 30V. The optimized design parameters of the MEMS Switch can be selected by the analysis of the mechanical behavior and the use of ANSYS simulation method.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.411-414
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• 2014

A switch is one of the most useful circuits for controlling the path of signal transmission. It can be added to digital circuits to create a kind of gate-level device and it can also save information into memory. In RF subsystems, a switch is used in a different way than its general role in digital circuits. The most important characteristic to consider when designing an RF switch is keeping the isolation as high as possible while also keeping insertion loss as low as possible. For high isolation, we propose leakage signal cancellation and inductive switching for designing a singlepole double-throw (SPDT) RF switch. By using the proposed method, an isolation level of more than 23 dB can be achieved. Furthermore, the heterojunction bipolar transistor (HBT) process is used in the RF switch design to keep the insertion loss low. It is demonstrated that the proposed RF switch has an insertion loss of less than 2 dB. The RF switch operates from 1 to 8 GHz based on the $0.18-{\mu}m$ SiGe HBT process, taking up an area of $0.3mm^2$.