• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.9 no.1
• /
• pp.103-107
• /
• 2009

In this paper, we designed and implemented a dual band chip antenna for WLAN, which contains within the small LAN card contrary to the enternal AP(Access Point) antenna. Limiting about the antenna size, we used dielectrics of high permittivity. Totally considering problems of demand-supply, price and characteristics, we used that relative dielectrics of ceramic is 9.8 and the thickness is 3.5mm and 5mm. Ceramic antenna can be used not only triple mode of IEEE 802.11.a,g and b but also broadband. The frequency bands have wideband characteristics of 2.4~2.5GHz and 4.9~5.85GHz and relatively constant performance.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.5
• /
• pp.889-895
• /
• 2008

In this paper a Fractional-N frequency synthesizer is designed for UHF RFID readers. It satisfies the ISO/IEC frequency band($860{\sim}960MHz$) and is also applicable to mobile RFID readers. A VCO is designed to operate at 1.8GHz band such that the LO pulling effect is minimized. The 900MHz differential I/Q LO signals are obtained by dividing the differential signal from an integrated 1.8GHz VCO. It is designed using a $0.18{\mu}m$ RF CMOS process. The measured results show that the designed circuit has a phase noise of -103dBc/Hz at 100KHz offset and consumes 9mA from a 1.8V supply. The channel switching time of $10{\mu}s$ over 5MHz transition have been achieved, and the chip size including PADs is $1.8{\times}0.99mm^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.219-222
• /
• 2003

In this paper, we designed a Ku-band BPF(Band Pass Filter) by microstrip line that most usually used a microwave device design and fabrication. Here a substrate of designed BPF were silicon substrate(${\varepsilon}_r=11.8$), and metal line was copper and silver/copper structure. And a configration of BPF was used hairpin pattern. A center frequency of designed BPF was 10GHz and their FBW(Fractional Band Width) was 20%(2GHz). It presented simulated results obtained for a 10GHz filter which yields an insertion loss of 0.1dB that ripple value related chebyshev reponse. Finallt we tried to make that a 30dB attenuation frequency was 20% of center frequency.

• Journal of electromagnetic engineering and science
• /
• v.18 no.3
• /
• pp.188-198
• /
• 2018

In this study, we propose an approach for the design and satisfy the requirements of the fabrication of a small, lightweight, reliable, and stable ultra-wideband receiver for millimeter-wave bands and the contents of the approach. In this paper, we designed and fabricated a stable receiver with having low noise figure, flat gain characteristics, and low noise characteristics, suitable for millimeter-wave bands. The method uses the chip-and-wire process for the assembly and operation of a bare MMIC device. In order to compensate for the mismatch between the components used in the receiver, an amplifier, mixer, multiplier, and filter suitable for wideband frequency characteristics were designed and applied to the receiver. To improve the low frequency and narrow bandwidth of existing products, mathematical modeling of the wideband receiver was performed and based on this spurious signals generated from complex local oscillation signals were designed so as not to affect the RF path. In the ultra-wideband receiver, the gain was between 22.2 dB and 28.5 dB at Band A (input frequency, 18-26 GHz) with a flatness of approximately 6.3 dB, while the gain was between 21.9 dB and 26.0 dB at Band B (input frequency, 26-40 GHz) with a flatness of approximately 4.1 dB. The measured value of the noise figure at Band A was 7.92 dB and the maximum value of noise figure, measured at Band B was 8.58 dB. The leakage signal of the local oscillator (LO) was -97.3 dBm and -90 dBm at the 33 GHz and 44 GHz path, respectively. Measurement was made at the 15 GHz IF output of band A (LO, 33 GHz) and the suppression characteristic obtained through the measurement was approximately 30 dBc.

• Journal of electromagnetic engineering and science
• /
• v.13 no.2
• /
• pp.93-103
• /
• 2013

This paper presented a novel approach for the design of a tunable dual-band bandpass filter (BPF) with independently tunable passband center frequencies and bandwidths. The newly proposed dual-band filter principally comprised two dual-mode single band filters using common input/output lines. Each single BPF was realized using a varactor-loaded transmission line resonator. To suppress the harmonics over a broad bandwidth, a defected ground structure was used at the input/output feeding lines. From the experimental results, it was found that the proposed filter exhibited the first passband center frequency tunable range from 1.48 to 1.8 GHz with a 3-dB fractional bandwidth (FBW) variation from 5.76% to 8.55%, while the second passband center's frequency tunable range was 2.40 to 2.88 GHz with a 3-dB FBW variation from 8.28% to 12.42%. The measured results of the proposed filters showed a rejection level of 19 dB up to more than 10 times the highest center frequency of the first passband.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.1
• /
• pp.138-143
• /
• 2009

In this paper, a novel ultra-wide band filter which is operating at frequency bands from 3.1 GHz to 10.6 GHz is suggested. It is modified from the conventional ring filter and consisted of a ring with two parallel open-stub with length of ${\lambda}/8$. It improves the sharpness of the conventional ring filter and is compact. The measured results show that the fabricated filter has a insertion loss of 2.1 dB and the measured group delay of the filter is less than 463 ps through UWB frequency bands.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.11
• /
• pp.48-53
• /
• 2007

In this paper, a high LO-RF isolation W-band MIMIC single-balanced mixer was designed and fabricated using a branch line coupler and a ${\lambda}/4$ transmission line. The W-band MIMIC single-balanced mixer was designed using the $0.1\;{\mu}m$ InGaAs/InAlAs/GaAs Metamorphic HEMT diode. The fabricated MHEMT was obtained the cut-off frequency($f_T$) of 154 GHz and the maximum oscillation frequency($f_{max}$) of 454 GHz. The designed MIMIC single-balanced mixer was fabricated using $0.1\;{\mu}m$ MHEMT MIMIC process. From the measurement, the conversion loss of the single-balanced mixer was 12.8 dB at an LO power of 8.6 dBm. P1 dB(1 dB compression point) of input and output were 5 dBm and -8.9 dBm, respectively. The LO-RF isolations of single-balanced mixer was obtained 37.2 dB at 94 GHz. We obtained in this study a higher LO-RF isolation compared to some other balanced mixers in millimeter-wave frequencies.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.8
• /
• pp.443-446
• /
• 2004

In this paper, a multi-band ceramic chip antenna for WLAN(Wireless LAN) applications is designed. The design target is to obtain 0 dBi of coverage gain with omni directional radiation pattern. The antenna is fabricated using Low Temperature Co-fired Ceramic(LTCC) technology. The size of the chip antenna is $2.2{\times}9.65{\times}1.02$mm. The measured antenna gain is 1 dBi at 2.44 GHz and 0.5 dBi at 5.5 GHz. The omni directional radiation pattern for the two operating bands is obtained. The measured bandwidth(S11=-10 dB) are 90 MHz at 2.44 GHz and 1280 MHz at 5.5 GHz respectively

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.7
• /
• pp.606-612
• /
• 2015

This paper proposes a new design of a dual-band orthogonal-polarization microstrip antenna for V2N(Vehicle to Nomadic Device) communication system. The proposed antenna consists of a perpendicular feeding structure for utilizing orthogonal linear polarizations and an microstrip radiator which loaded by close-looped H-shape slot for obtaining dual-band operation. Due to the geometrically different loading effect of the close-looped H-shape slot for each feeding location, the orthogonally linear polarization at dual-band operation of the proposed antenna can be successfully achieved. The proposed antenna theoretically and experimentally demonstrates the vertical linear polarization at the operating frequency of 1.8 GHz and the horizontal linear polarization at the operating frequency of 2.4 GHz, respectively. The simulation and measurement results of the implemented antenna have been in good agreement with the reflection coefficients, radiation patterns, and realized antenna gains.

• 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.