• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.2
• /
• pp.137-144
• /
• 2008

In this paper, a novel voltage-controlled oscillator(VCO) using the output matching network based on the harmonic control circuit is presented for improving the phase noise property. The phase noise suppression is achieved through the harmonic control circuit having the short impedances for both second-harmonic and third-harmonic components, which has been connected at the output matching network. Also, we have used the microstrip square open loop multiple split-ring resonator(OLMSRR) having the high-Q property to further reduce the phase noise of VCO. Because the output matching network based on the harmonic control circuit has been used for reducing the phase noise property instead of the High-Q resonator, we can obtain the broad tuning range by the low-Q resonator. The phase noise of the proposed VCO using the output matching network based on the harmonic control circuit and the microstrip square OLMSRR has been $-127.5{\sim}126.33$ dBc/Hz @ 100 kHz in the tuning range, $5.744{\sim}5.839$ GHz. Compared with the reference VCO using the output matching network without the harmonic control circuit and the microstrip line resonator, the phase noise property of the proposed VCO has been improved in 26.66 dB.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.52 no.6
• /
• pp.702-708
• /
• 2019

The range resolution of echo sounders can be improved by enhancing the transducer bandwidth. We designed a bandpass matching network for expanding the bandwidth of a transducer by scaling in both impedance and frequency after transforming a lowpass network into a bandpass configuration for a third-order Bessel filter. We measured the effect of the Bessel matching network for a 50 kHz sandwich type transducer on the transmitting voltage response (TVR), receiving sensitivity (SRT) and figure of merit (FOM), using a chirp echo sounder system. Both the simulation and experimental results indicated that the transducer with a bandpass matching network was capable of producing a symmetrical acoustic output over a wider bandwidth (8.25 kHz) than was the transducer without a matching network (3.75 kHz). By implementing the Bessel matching network, we achieved a 120% bandwidth enhancement.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.7
• /
• pp.807-815
• /
• 2019

In this paper, we design a power amplifier to support quad-band in wireless communication devices using RF CMOS 180-nm process. The proposed power amplifier consists of low-band 0.9, 1.8, and 2.4 GHz and high-band 5 GHz. We proposed a structure that can support each input matching network without using a switch. For maximum linear output power, the output matching network was designed for impedance conversion to the power matching point. The fabricated quad-band power amplifier was verified using modulation signals. The long-term evolution(LTE) 10 MHz modulated signal was used for 0.9 and 1.8 GHz, and the measured output power is 23.55 and 24.23 dBm, respectively. The LTE 20 MHz modulated signal was used for 1.8 GHz, and the measured output power is 22.24 dBm. The wireless local area network(WLAN) 802.11n modulated signal was used for 2.4 GHz and 5.0 GHz. We obtain maximum linear output power of 20.58 dBm at 2.4 GHz and 17.7 dBm at 5.0 GHz.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.16 no.5
• /
• pp.179-186
• /
• 2021

For stereo matching based on deep learning, the design of network structure is crucial to the calculation of matching cost, and the time-consuming problem of convolutional neural network in image processing also needs to be solved urgently. In this paper, a method of stereo matching using sparse loss volume in parallax dimension is proposed. A sparse 3D loss volume is constructed by using a wide step length translation of the right view feature map, which reduces the video memory and computing resources required by the 3D convolution module by several times. In order to improve the accuracy of the algorithm, the nonlinear up-sampling of the matching loss in the parallax dimension is carried out by using the method of multi-category output, and the training model is combined with two kinds of loss functions. Compared with the benchmark algorithm, the proposed algorithm not only improves the accuracy but also shortens the running time by about 30%.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.2
• /
• pp.141-146
• /
• 2009

In this paper, a novel harmonic control circuit has been proposed for the design of high-efficiency power amplifier with Si LDMOSFET. The proposed harmonic control circuit haying the short impedances for the second- and third-harmonic components has been used to design the in/output matching network. The efficiency enhancement effect of the proposed harmonic control circuit is superior to the class-F or inverse class-F harmonic control circuit. Also, when the proposed harmonic control circuit has been adapted to the input matching network as well as the output matching network, the of ficiency enhancement effect of the proposed power amplifier has increased all the more. The measured maximum power added efficiency (PAE) of the proposed power amplifier is 82.68% at 1.71GHz band. Compared with class-F and inverse class-F amplifiers, the measured maximum PAE of the proposed power amplifier has increased in $5.08{\sim}9.91%$.

• Current Optics and Photonics
• /
• v.2 no.5
• /
• pp.407-412
• /
• 2018

An optimal matching approach is proposed to maximally ensure the output power uniformity of the cascaded encoder in the passive optical network (PON) monitoring system based on a remote coding scheme. The calculation results show that the optimum arrangement can effectively reduce the difference of the total insertion loss in comparison to the random arrangement (i.e., 0.07 dB vs 2.67 dB in the cascaded encoder with 16 output ports). The proposed approach realizes the optimum configuration for the $1{\times}2$ optical splitters used without adding any extra components. The test results of the fabricated cascaded encoder with 32 output ports prove the feasibility of the proposed approach.

• Journal of Power Electronics
• /
• v.16 no.6
• /
• pp.2338-2349
• /
• 2016

This paper presents an impedance-matching-based control scheme for the harmonic resonance damping of multiple grid-connected-converters (GCCs) with LCL filters. As indicated in this paper, harmonic resonance occurs if a GCC possesses an output impedance that is not matched with the rest of the network in some specific frequency bands. It is also revealed that the resonance frequency is associated with the number of GCCs, the grid impedance and even the capacitive loads. By controlling the grid-side current instead of the converter-side current, the critical LCL filter is restricted as an internal component. Thus, the closed-loop output impedance of the GCC within the filter can be configured. The proposed scheme actively regulates the output impedance of the GCC to match the impedance of the external network, based on the detected resonance frequency. As a result, the resonance risk of multiple GCCs can be avoided, which is beneficial for the plug-and-play property of the GCCs in microgrids. Simulation and experimental results validate the effectiveness of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.1
• /
• pp.114-121
• /
• 2003

In this paper, low voltage and two stage CMOS Class E RF power amplifier for ISM(Industrial/Scientific/Medical) Open Band is presented. The power amplifier operates at 2.4GHz frequency, and is designed and simulated with a 0.35um CMOS technology and HSPICE simulator. The power amplifier is simple structure of two stage Class E power amplifier. The design procedure determing matching network was presented. The power amplifier is composed of input stage matching network, preamplifier, interstage matching network, power amplifier, and output stage matching network. The matching networks of input stage and interstage were constituted by pi($\pi$) type and L type respectively. At 2.4GHz operating frequency, and with a 2.5V supply voltage, the power amplifier delivers 23dBm output power to a 50${\Omega}$ load with 39% power added efficiency(PAE).

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.9 no.4
• /
• pp.192-197
• /
• 2009

This paper presents the design and measurement of a 2.4/5.2-GHz dual band VCO with a balanced frequency doubler in $0.18\;{\mu}m$ CMOS process. The topology of a 2.4 GHz VCO is a cross-coupled VCO with a LC tank and the frequency of the VCO is doubled by a frequency balanced doubler for a 5.2 GHz VCO. The gate bias matching network for class B operation in the balanced doubler is adopted to obtain as much power at 2nd harmonic output as possible. The average output powers of the 2.4 GHz and 5.2 GHz VCOs are -12 dBm and -13 dBm, respectively, the doubled VCO has fundamental harmonic suppression of -25 dB. The measured phase noises at 5 MHz frequency offset are -123 dBc /Hz from 2.6 GHz and -118 dBc /Hz from 5.1 GHz. The total size of the dual band VCO is $1.0\;mm{\times}0.9\;mm$ including pads.

• Proceedings of the IEEK Conference
• /
• 2001.06a
• /
• pp.169-172
• /
• 2001

This paper has been studied a calibration techniques for monopole antenna in the frequency range 150 KHz to 30 MHz. The long wavelength associated with the low frequency, methods used to calibrate or characterize antennas at higher frequencies are not applicable. The equivalent capacitance substitution method uses a dummy antenna in place of the actual rod element See figure 1. for guidance in making a dummy antenna. Set up the matching network to be characterized and the measuring equipment as shown in Figure 2. Subtract the measured output of the matching network from the measured output of the signal generator and subtract -6 dB(for the 1 m rod). Measurements made at a sufficient number of frequencies number of frequencies to obtain a smooth curve of antenna factor.(fig 5.)