Yohan Jang

Design of a multiband internal antenna for mobile application

The multiband internal antenna for mobile application is proposed. The proposed antenna has wide bandwidth of about 400 MHz (2.3 GHz ∼ 2.69 GHz) for MIMO antenna. The return loss(S<inf>11</inf> and S<inf>22</inf>) is higher than 10 dB and isolation characteristic(S<inf>12</inf> and S<inf>21</inf>) is less than −20 dB over the frequency band of interest. The separate monopole antenna has return loss of higher than 10 dB over WCDMA band. The measured antenna gain is higher than 0 dBi and measured efficiency is greater than 60 %.

Design of a High Efficiency Resonator for Wireless Power Transfer

In this paper, an efficiency improvement method in the wireless power transfer system based on magnetic resonance is proposed. A combined helical-spiral structure is adopted for self-resonant coil and source and device coils are designed using circular loop structure. The proposed resonator utilizing combined helical-spiral structure yields 13 % efficiency improvement over that of an existing helical type resonator when the transmitting and receiving coils are separated by 120 mm. In addition, the size can be reduced by 33 % comparing to the previous resonator.

Design of a 1~10 GHz High Gain Current Reused Low Noise Amplifier in 0.18 ㎛ CMOS Technology

In this paper, we propose a high gain, current reused ultra wideband (UWB) low noise amplifier (LNA) that uses TSMC 0.18 ㎛ CMOS technology. To satisfy the wide input matching and high voltage gain requirements with low power consumption, a resistive current reused technique is utilized in the first stage. A π-type LC network is adopted in the second stage to achieve sufficient gain over the entire frequency band. The proposed UWB LNA has a voltage gain of 12.9～18.1 ㏈ and a noise figure (NF) of 4.05～6.21 ㏈ over the frequency band of interest (1～10 ㎓). The total power consumption of the proposed UWB LNA is 10.1 ㎽ from a 1.4 V supply voltage, and the chip area is 0.95×0.9 ㎜.

Design of an Ultra Low Power CMOS 2.4 GHz LNA

In this paper, we proposed an ultra-low power low noise amplifier(LNA) using a TSMC 0.18 RF CMOS process. To satisfy the low power consumption with high gain, a current-reused technique is utilized. In addition, a low bias voltage in the subthreshold region is utilized to achieve ultra low power characteristic. The designed LNA has the voltage gain of 13.8 dB and noise figure(NF) of 3.4 dB at 2.4 GHz. The total power consumption of the designed LNA is only 0.63 mW from 0.9 V supply voltage and chip occupies area.

Design of an internal antenna for DVB-H mobile application

An internal antenna with a system ground for DVB-H application is proposed. The proposed antenna consists of a meander radiator and two stubs. The designed antenna has a broad impedance bandwidth to cover the whole DVB-H band. Therefore, the proposed antenna can be a good candidate for DVB-H mobile handset application since its size is small enough to satisfy the size constraint imposed on a mobile handset.