• Journal of Advanced Navigation Technology
• /
• v.21 no.1
• /
• pp.84-89
• /
• 2017

This paper presents a dual-wideband bandpass filter (BPF) with high band-to-band isolation and skirt selectivity using distributed composite right/left-handed (CRLH) transmission line (TL) quad-mode resonators (QMRs). The results of the proposed distributed CRLH TL unit cell analysis are used to establish the scattering parameters and the resonance frequencies of the QMR constituting the dual-wideband BPF. A novel dual-wideband bandpass filter is designed and fabricated, using the derived scattering characteristics. The measured results show that the fabricated dual-wideband bandpass filter has an insertion loss of less than 1.08dB in the lower band, and of 2.01dB in the upper band, a bandwidth of 2.8-5.52GHz and 9.68-12.26GHz, and a band-to-band isolation of more than 38dB, from 6.34-8.42GHz.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.4 no.3
• /
• pp.557-564
• /
• 2000

A microstrip band-pass filter using cross-coupled resonators is designed and studied experimentally. The cross-coupled microstrip hairpin resonator filters exhibit ripples in both passband and stopband. These ripples can improve both frequency selectivity and insertion loss. The cross-coupled filters are not only simple and compact in configuration, but also have great flexibility to form filters into a variety of size. In this paper, a microstrip band-pass filter using cross-coupled resonators is designed at the center frequency of 1.8GHz with bandwidth of 5.0% using Ensemble software. The experimental results show that the bandwidth is about 4.53% at 1.8GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.9
• /
• pp.833-839
• /
• 2011

This paper has suggested a technique for measuring VSWR at 1.8 GHz band for various modulated signals. By using directional coupler the power of incident and reflected wave is measured, and in order to minimize the size and cost of the measuring circuit, a SPDT(Single Pole Double Throw) switch is adopted to realize the circuit with just one detector and one A/D(Analog to Digital) converter. MCU(Micro Control Unit) is used to calculate the voltage reflection coefficient and VSWR, and the measured VSWR error has improved by approximately 0.2 with applying a simple bubble sorting algorithm to reduce the measurement error, the MCU process time and load.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.6
• /
• pp.84-90
• /
• 2011

In this paper, a dual-band pseudo-combline narrow bandpass filter is proposed. The proposed bandpass filter adopts the open resonant stubs and the proposed bandpass filter can be used for ITS(Intelligent Transport System) and X-band satellite systems application. The proposed bandpass filter has the insertion and return losses of 1.72 dB and 15.5 dB at the bandwidth of 3.6 % and center frequency of 5.8 GHz, respectively. Also, the second operating frequency band for insertion and return losses are 1.92 dB and 16.3 dB at the bandwidth of 3% and center frequency of 8.5 GHz, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.11B
• /
• pp.1595-1599
• /
• 2001

In this paper, we have desired and implemented of ASK modulator MMIC operating at 5.8 GHz for OBE used in AGPS(Automatic Gate Passing System). The proposed ASK modulator MMIC was implemented to apply a single supply voltage of 3 V to the drain in order to decrease ACP(Adjacent Channel Power). As a result, it is exhibits a broad linear modulation range from 0.7 V to 3 V and an On/off characteristic over 40 dB. The layouts of ASK modulator MMICs was designed and fabricated by using ETRI 0.57m MESFET library The chip size was 1.0mm $\times$x1.0mm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.1004-1007
• /
• 2005

This paper presents a programmable RF BIST (Built-in Self-Test) circuit for low noise amplifiers. We have developed a new on-chip RF BIST circuit that measures RF parameters of low noise amplifier (LNA) using only DC measurements. The BIST circuit contains test amplifier with programmable capacitor banks and RF peak detectors. The test circuit utilizes output DC voltage measurements and these measured values are translated into the LNA specifications such as input impedance and gain using the mathematical equations. Our on-chip BIST can be self programmed for 1.8GHz, 2.4GHz and 5.25GHz LNA for GSM, Bluetooth and IEEE802.11g standards.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.4
• /
• pp.441-448
• /
• 2015

In this paper, a CPW-fed dual-band monopole antenna with two branch strips for WLAN(Wireless Local Area Networks) applications was designed, fabricated and measured. The proposed antenna is based on a CPW-feeding structure, and composed of two branch strips and then designed and tuned the length of two branch lines to obtained required frequencies bands. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS) and carried out simulation about parameters $L_5$, $L_8$, $W_3$, $W_5$, $W_9$. The proposed antenna is fabricated on the FR-4 substrate using the obtained parameters. The numerical and experiment results demonstrated that the proposed antenna obtained the -10 dB impedance bandwidth 1,095 MHz (1.57~2.665 GHz) for 2.4 GHz band and 1,680 MHz (4.99~6.67 GHz) for 5 GHz band satisfied requirement while simultaneously covering the WLAN bands. And characteristics of gain and radiation patterns are determined for WLAN operating bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.12
• /
• pp.1337-1342
• /
• 2012

In this paper, we propose a novel reconfigurable antenna that can change the electrical shape of the matching network using RF switches of PIN diodes. The designed antenna operates at two different modes that are Mode 1 (HSDPA band, 2.1~2.2 GHz) and Mode 2(WiBro WiFi band, 2.3~2.5 GHz). The antenna is built on both sides of a polyarcylate substrate. The measured reflection coefficient shows a matching bandwidth of 547 MHz($S_{11}$ <-3 dB, 2.035~2.582 GHz) for Mode 1 and 600 MHz($S_{11}$ <-3 dB, 2.2~2.8 GHz) for Mode 2, and it shows average vertical gains of -4.4 dBi and -4.5 dBi in x-y plane, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.5
• /
• pp.688-693
• /
• 2022

In this paper, channel propagation path loss was measured in building corridors for frequency bands of 3.7 GHz and 28 GHz, which are used in 5G mobile communication, and compared and analyzed with CI (Close-In) and FI (Floating-Intercept) channel models. To measure the propagation path loss, the measurement was performed while moving the receiver (Rx) from the transmitter (Tx) by 10 m. As a result of the measurement, the PLE (Path Loss Exponent) values of the CI model at 3.7 GHz and 28 GHz were 1.5293 and 1.7795, respectively, and the standard deviations were analyzed as 9.1606 and 8.5803, respectively. In the FI model, 𝛼 values were 79.5269 and 70.2012, 𝛽 values were -0.6082 and 1.2517, respectively, and the standard deviations were 5.8113 and 4.4810, respectively. In the analysis results through the CI model and the FI model, the standard deviation of the FI model is smaller than that of the CI model, so it can be seen that the FI model is similar to the actual measurement result.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.48 no.12
• /
• pp.45-51
• /
• 2011

This paper presents a wideband low-noise amplifier (LNA) covering 800MHz~5.8GHz for various wireless communication standards by utilizing in a 0.13um CMOS technology. Particularly, the LNA consists of two stages to improve the low-noise characteristics, that is, a cascode input stage and an output buffer with noise cancellation technique. Also, a feedback resistor is exploited to help achieve wideband impedance matching and wide bandwidth. Measure results demonstrate the bandwidth of 811MHz~5.8GHz, the maximum gain of 11.7dB within the bandwidth, the noise figure of 2.58~5.11dB. The chip occupies the area of $0.7{\times}0.9mm^2$, including pads. DC measurements reveal the power consumption of 12mW from a single 1.2V supply.