• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1098-1106
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• 2007

This paper presents active antenna diplexers implemented into an ultra-wideband CPW(Coplanar Waveguide) fed monopole antennas. The proposed active antenna diplexer is designed to direct interconnect the output port of a wideband antenna to the input port of two active(HEMT) devices, where the impedance matching conditions of the proposed active integrated antenna are optimized by adjusting CPW(Coplanar Waveguide) feed line to be the length of 1/20 $\lambda_0$(@5.8 GHz) in planar type wideband antenna. The measured bandwidth of the active integrated antenna shows the range from 2.0 GHz to 3.1 GHz and from 5.25 GHz to 5.9 GHz. The measured peak gains are 17.0 dB at 2.4 GHz and 15.0 dB at 5.5 GHz.

• ETRI Journal
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• v.27 no.2
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• pp.166-171
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• 2005

In this paper, a synthesis technique for nonuniform filtering structures to be employed in active integrated antenna layouts is presented. The idea is to suppress the higher harmonic contribution due to the presence of nonlinear components through a nonuniform transmission line properly designed via Orlov's synthesis formula. The theory presented is applied here to synthesize an amplifier-based active antenna layout for wireless local area network (WLAN) purposes working at 2.4 GHz. The numerical results presented show the capabilities of the proposed approach.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1807-1813
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• 2007

This paper deals with extending the variable natural oscillation frequency range of an active integrated FET oscillator. In this paper, we conform experimentally that the variable range of the natural oscillation frequency is expanded about three times in the oscillator controlled by the varactor diode. When the frequency difference is given to the oscillators in the two element antenna system, phase difference appeared between the oscillators. The 2-, 3-, 4-, 5-element patch antenna arrays are composed for the beam scanning experiments. All the above patch antennas show good phased array characteristics. The range of the scanning angle is about $30^{\circ}$, and the radiation power is gradually increased from $50{\mu}W\;to\;200{\mu}W$. The radiation patterns we sharpened as the number of elements is increased.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.2
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• pp.87-92
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• 2009

In this paper, we designed and fabricated the active amplification block for the integrated antenna module. The fabricated amplification module have a proper gain and low noise figure in the band of AM/FM band, T-DMB band and GPS band, and show good isolation performance for each band. Manufactured circuits satisfied the gain performance 7 dB in AM band, 11 dB in FM band, 10 dB in T-DMB, and 17 dB in GPS band. The integrated amplification block was realized by 35 mm*35 mm size, and was shown as the same sensitivity performance as compared with a conventional reference antennas.

• ETRI Journal
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• v.46 no.2
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• pp.323-332
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• 2024

Receiver and transmitter monolithic microwave integrated circuit (MMIC) multifunction chips (MFCs) for active phased-array antennas for Ka-band satellite communication (SATCOM) terminals have been designed and fabricated using a 0.15-㎛ GaAs pseudomorphic high-electron mobility transistor (pHEMT) process. The MFCs consist of four-channel radio frequency (RF) paths and a 4:1 combiner. Each channel provides several functions such as signal amplification, 6-bit phase shifting, and 5-bit attenuation with a 44-bit serial-to-parallel converter (SPC). RF pads are implemented on the bottom side of the chip to remove the parasitic inductance induced by wire bonding. The area of the fabricated chips is 5.2 mm × 4.2 mm. The receiver chip exhibits a gain of 18 dB and a noise figure of 2.0 dB over a frequency range from 17 GHz to 21 GHz with a low direct current (DC) power of 0.36 W. The transmitter chip provides a gain of 20 dB and a 1-dB gain compression point (P1dB) of 18.4 dBm over a frequency range from 28 GHz to 31 GHz with a low DC power of 0.85 W. The P1dB can be increased to 20.6 dBm at a higher bias of +4.5 V.

• Journal of Satellite, Information and Communications
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• v.1 no.1
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• pp.54-58
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• 2006

A new design for easily controlling operating frequency of an antenna-integrated planar oscillator is introduced. The oscillator circuit of a broadband negative-resistance active part and a passive load including a patch antenna. The patch resonance is used for determining the oscillation frequency. This design reduces the possibility of mismatch between antenna radiation and oscillation frequencies. To achieve optimum output power, load-pull simulation for the negative-resistance circuit is used. The load-pull simulation shows the feed point and the delay of feed line can affect the oscillation power. Two negative-resistance circuits capable of supporting oscillation over full C-band and X-band are fabricated. The oscillation frequency, output power and phase noise for different patch antennas are measured.

• ETRI Journal
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• v.35 no.3
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• pp.378-385
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• 2013

An S-band multifunction chip with a simple interface for an active phased array base station antenna for next-generation mobile communications is designed and fabricated using commercial 0.5-${\mu}m$ GaAs pHEMT technology. To reduce the cost of the module assembly and to reduce the number of chip interfaces for a compact transmit/receive module, a digital serial-to-parallel converter and an active bias circuit are integrated into the designed chip. The chip can be controlled and driven using only five interfaces. With 6-bit phase shifting and 6-bit attenuation, it provides a wideband performance employing a shunt-feedback technique for amplifiers. With a compact size of 16 $mm^2$ ($4mm{\times}4mm$), the proposed chip exhibits a gain of 26 dB, a P1dB of 12 dBm, and a noise figure of 3.5 dB over a wide frequency range of 1.8 GHz to 3.2 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.286-291
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• 2013

In this paper, a compact rectenna system is designed using a circular sector antenna with harmonic-rejecting characteristics and a direct impedance matching method. The system is designed with bandpass filtering performed by the harmonic-rejection of the circular sector antenna and without impedance matching circuit for the diodes by the direct impedance matching technique. Therefore, while the rectifying circuit of the proposed system can be implemented without a bandpass filter and a impedance matching circuit, it is integrated on the back side of the antenna using precise fabrication techniques for coaxial feedings without degrading the system performances corresponding to the feeding points. From the experimental results, the optimized rectenna system has presented excellent performances of a conversion efficiency of more than 52 % and a conversion voltages of more than 1.5 V at 2.5 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1050-1060
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• 2009

In this paper, a X-Band T/R-module for SAR(Synthetic Aperture Radar) systems based on active phased array antennas is designed and fabricated. The T/R modules have a and width of more than 800 MHz centered at X-Band and support dual, switched polarizations. The output power of the module is 7 watts over a wide bandwidth. The noise figure is as low as 3.9 dB. Phase and amplitude are controlled by a 6-bit phase shifter and a 6-bit digital attenuator, respectively. Further the fabricated T/R module has est and calibration port with directional coupler and power divider. Highly integrated T/R module is achieved by using LTCC(Low Temperature Co-fired Ceramic) multiple layer substrate. RMS gain error is less than 0.8 dB max. in Rx mode, and RMS phase error is less than $4^{\circ}$ max. in Rx/Tx phase under all operating frequency band, or the T/R module meet the required electrical performance m test. This structure an be applied to active phase array SAR Antennas.