• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.17-20
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• 2000

This study is about a retrograde triple well employed in the Cell tr. of next DRAM and flash memory. triple well structure is formed deep n-well under the light p-well using MeV ion implantation. MeV P implanted deep n-well was observed to show greatly improved characteristics of electrical isolation and soft error. Junction leakage current, however, showed a critical behavior as a function of implantation and annealing conditions. {311} defects were observed to be responsible for the leakage current. {311} defects were generated near the R$\sub$p/ (projected range) region and grown upward to the surface during annealing. This is study on the defect behavior in device region as a function of implantation and annealing conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.09a
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• pp.89-94
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• 1996

In this paper A methode for design of hybrid-ring couplers having sections of lenth λ/n is proposed. Assuming only one - axis symmitry and isolation of output arms general expressions for the scattering parameters are obtained. The new design method using λ/n sections for 3 dB couplers is derived, . The calculated frequency reponse of the new design has been compared with that of conventional ones, . A new design using λ/5 section and having an overall length 13λ/10 is found to be superior to the 7λ/6 design is expected to have a low insertion loss by virtue of its shorter length.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.6
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• pp.637-645
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• 2014

This paper presents a new $4{\times}4$ multi-port amplifier(MPA) structure using reconfigurable switching matrices as input and output hybrid matrices(IHM, OHM), and phase/amplitude error calibration circuits. According to the mode selection of the switches, output power can be flexibly and effectively managed since the number of PA's to be used and the number of output port to distribute/combine amplified signals can be controlled. In addition, the proposed structure contains the phase and amplitude error calibration block that helps produce identical amplitudes and desired phase differences to the $4{\times}4$ OHM, resulting in optimizing the port-to-port isolation of the MPA system.

• Journal of Navigation and Port Research
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• v.29 no.7
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• pp.615-618
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• 2005

A new structure of the Wilkinson power divider that can suppress multiple harmonics output is presented The power divider consists of T-type or $\pi$-type capacitive loads and shunt resistors. Experimental results show that this power divider suppresses the second and the third harmonic components to less than -38dB, while maintaining the characteristics of a conventional Wilkinson power divider, featuring an equal power split, a simultaneous impedance matching at all ports and a good isolation between output ports.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.647-655
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• 2003

Commonly used SAW duplexers have a difficulty on manufacture so that a transmission line is printed on the package or an LTCC multi-layer is needed because a quarter-wave transmission line which is a kind of an isolation network is applied to the SAW duplexers. In this study, new structures of one chip type SAW duplexers are proposed. In the proposed structure, Tx and Rx SAW ladder filters and isolation networks are located on a single 36LiTaO$_3$ piezoelectric substrate. The manufacture process is very simple than commonly used product. It is possible to improve tile performance by means of optimizing the micro-strip line lumped elements. It is easy to integrate and modulate with other surrounding components. The optimal design techniques can be applied to other kind of multi-port devices.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.921-924
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• 2005

We report low conversion loss and high LO to RF isolation 94 GHz MMIC resistive mixers based on 0.1 ${\mu}m$ InGaAs/InAlAs/GaAs metamorphic HEMT technology. The fabricated resistive mixers applied a one-stage amplifier on RF port of the mixer. By using the one-stage amplifier, we obtained the decrement of conversion loss and the increment of LO to RF isolation. So, we can obtain higher performances than conventional resistive mixers. The modified mixer shows excellent conversion loss of 6.7 dB at a LO power of 10 dBm. We also observed an extremely high isolation characteristic from the MMICs exhibiting the LO-RF isolation of 21 ${\pm}$ 0.5dB in a frequency range of 93.7${\sim}$ 94.3 GHz. The low conversion loss and high LO-RF isolation characteristics of the MMIC modified resistive mixers are mainly attributed to the performance of the MHEMTs exhibiting a maximum transconductance of 654 mS/mm, a current gain cut-off frequency of 173 GHz and a maximum oscillation frequency of 271 GHz.

• ETRI Journal
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• v.36 no.1
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• pp.116-123
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• 2014

In this paper, a novel unequal broadband out-of-phase power divider (PD) is presented. Double-sided parallel-strip lines (DSPSLs) are employed to achieve an out-of-phase response. Also, an asymmetric dual-band matching structure with two external isolation resistors is utilized to obtain arbitrary unequal power division, in which the resistors are directly grounded for heat sinking. A through ground via (TGV), connecting the top and bottom sides of the DSPSLs, is used to short the isolation components. Additionally, this property can efficiently improve the broadband matching and isolation bandwidths. To investigate the proposed divider in detail, a set of design equations are derived based on the circuit theory and transmission line theory. The theoretical analysis shows that broadband responses can be obtained as proper frequency ratios are adopted. To verify the proposed concept, a sample divider with a power division of 2:1 is demonstrated. The measured results exhibit a broad bandwidth from 1.19 GHz to 2.19 GHz (59.2%) with a return loss better than 10 dB and port isolation of 18 dB.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.5
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• pp.595-604
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• 2016

Utilizing a standard 130-nm CMOS process, a RF frontend is designed at 24 GHz for automotive collision avoidance radar application. Single IF direct conversion receiver (DCR) architecture is adopted to achieve high integration level and to alleviate the DCR problem. The proposed frontend is composed of a two-stage LNA and downconversion mixers. To save power consumption, and to enhance gain and linearity, stacked NMOS-PMOS $g_m$-boosting technique is employed in the design of LNA as the first stage. The switch transistors in the mixing stage are biased in subthreshold region to achieve low power consumption. The single balanced mixer is designed in PMOS transistors and is also realized based on the well-known folded architecture to increase voltage headroom. This frontend circuit features enhancement in gain, linearity, and power dissipation. The proposed circuit showed a maximum conversion gain of 19.6 dB and noise figure of 3 dB at the operation frequency. It also showed input and output return losses of less than -10 dB within bandwidth. Furthermore, the port-to-port isolation illustrated excellent characteristic between two ports. This frontend showed the third-order input intercept point (IIP3) of 3 dBm for the whole circuit with power dissipation of 6.5 mW from a 1.5 V supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.53-59
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• 2002

In this paper, we present design results for an orthomode transducer(OMT) to be used in multi-band antenna feeds. The OMT is realized in the form of a tapered square waveguide, where 18-20 GHz ports are placed in the taper region normal to the waveguide axis, while 30-45 GHz ports are placed in line with the waveguide axis. The reflection coefficient of each port is designed to be less than 20 dB, while the isolation between ports are greater than 15 dB. Thin septa are placed in side ports to reduce the effect of side ports on the return loss of the in-line port. The commercial software HFSS？ is used to design the whole structure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.52-58
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• 2008

Ths paper describes the Dual-band switch which was proposed new structure that could improved the specification of broadband and designed by the optimized structure through simulation. The Dual-band switch with 2.4[GHz]/5.8[GHz] that can apply to 802.11a/b/g system that is commercialized present was studied to get a new structure with higher power, high isolation. The transmitter of switch was designed to operate a parallel switching element with stack structure of two FET. The receiver designed to have asymmetry structure that insert series FET in addition to basic serial/parallel FET. SPDT(Single Pole Double Throw) Tx/Rx FET switch is a device that can do switching from a port of input to two port of output. The fabricated SPDT switch has the characteristic of insertion loss of a below -3[dB] form DC to 6[GHz] and the isolation of a below -30D[dB](Rx mode).