Bok-Ki Kim

K-band hair-pin resonator oscillators

K-band hair-pin resonator oscillators using a frequency doubler and the push-push method are presented in this paper. An HP EEsof Libra ver. 6.1 has been used for the nonlinear design of the oscillators. For the oscillators using the frequency doubler and the push-push method, the output power of 0.83 dBm and -1.67 dBm, and phase noise of -86 dBc/Hz and -90 dBc/Hz at the offset frequency of 100 kHz are obtained, respectively.

A Low Phase Noise Fully Integrated CMOS LC VCO Using a Large Gate Length pMOS Current Source and Bias Filtering Technique for 5-GHz WLAN

This paper presents a low phase noise fully integrated CMOS LC voltage-controlled oscillator (VCO) for 5-GHz WLAN applications. Low phase noise has been achieved by the use of the pMOS current source with a large gate length and bias filtering. The tail current source as well as the mirror has been kept large so that flicker-noise upconversion is minimized without degrading thermal noise. Bias filters are used in VCO to suppress reference current noise and dynamic transient effects on the bias line. The VCO is designed and implemented to evaluate the concept using 0.18-mum TSMC CMOS process. The VCO has a tuning range of 264 MHz and phase noise of -116 dBc/Hz at 1 MHz offset frequency at the 5.32-GHz carrier. The figure-of-merit (FOM) of the VCO is -183.1. This VCO consumes 3.17 mA from a 1.8 V supply.

A novel MIH handover procedure for efficient PMIPv6 network

In this paper, we proposed a new MIH handover procedure for resource efficiency and handover delay performance in the wireless link of MIH that offers seamless handover between heterogeneous networks. New transaction messages are proposed to indicate a handover event by the MN. We focus the application of our procedure to a handover scenario from mobile WiMAX to wireless LAN, and consider the qualitative performance analysis of handover delay. Based on its performance result, we can see that our proposed procedure works more efficiently than the existing handover procedure.

An Efficient PFMIPv6 and WLAN Interworking Scheme for Fast Handover

As the number of a smart phone user over the world surprisingly grows and a wireless Internet market expands, service requirement of a mobile terminal is increasing. However, because there is no consideration of mobility in the early standard step, it is difficult to expect to improve the service performance in handover procedure. This paper proposes a PFMIPv6 handover scheme by using probe request message and authentication message and by using buffering scheme in IEEE 802.11. In addition, we simulated this proposal scheme and verified that the proposed handover scheme is improved in terms of handover delay, and average FTP throughput during the handover period.

Resistive mixer with low IMD3 and high power level for 5.8 GHz wireless LAN application

In this paper, an improved hybrid-type resistive mixer for 5.8 GHz band wireless LAN was designed and fabricated in order to obtain low 3rd order inter-modulation distortion (IMD3) and high output power by the low LO power level. The IMD3 of the resistive mixer is 44.33 dBc with -5 dBm RF power at 5.8 GHz. In addition, the conversion loss and 3rd-order intercept point (IP3) are 7.83 dB and 12 dBm with 4 dBm LO power level, respectively. The isolations of LO/RF and LO/IF are 50 dB and 60 dB, respectively.

Design of a 5.8 GHz Broadband BPFs with Second Harmonics Suppression Using Open-Stubs

In this paper, integration of a broadband open-stub bandpass filters (BPFs) is presented. The second harmonics can be suppressed by combining the frequency selective coupling structure (FSCS) and quarter-wavelength using Z-transform technique. Newly developed BPFs reduce the size as compared to the conventional one by inserting the inverter between the stubs. Experiment results showed bandwidth of 95% with the center frequency of 5.8 GHz, insertion loss of -0.6 dB and return loss of -14 dB. The designed BPFs can be applied for C-band of satellite communication and intelligent transportation system (ITS) application.

Performance Analysis of a Fast Vertical Handover Scheme between MIH and PFMIPv6

For vertical handover, the part for the homogeneous handover needs to be modified, which allows users to utilize the various wireless access schemes with a mobile terminal with PFMIPv6. In this paper, we considered a cross-layer design for fast vertical handover between MIH and PFMIPv6, where two MIH-layer messages are suggested to reduce handover latency and integrate between MIH and PFMIPv6 efficiently. The proposed scheme is evaluated with handover latency. The results show that the proposed handover procedure reduces handover latency compared with the existing one.

Design of a 5.8 GHz Broad Band-Pass Filter with Second of Harmonics Suppression Using the Open Stubs

In this paper, a broadband open stubs band pass filters which can suppress the second harmonics using Z-transform technique, is designed, fabricated and characterized. The proposed broadband filters integrate the band stop filter with the FSCS structure and open stub in order to suppress the second harmonics. Due to insertion of BSF at input and output terminal, the size of the filter was increased in the conventional filter, however, in the proposed structure, the position of inverter that connects the stubs can be integrated between those stubs, thereby decreasing the size. So, it can be fabricated in the size of which is smaller size than conventional one. The measured results of the proposed filters have center frequency of a 5.8 GHz with bandwidth of 95 %, insertion loss of 0.6 dB, return loss of 14 dB. The simulation results are consistent with measurement results. The filter is designed far X-band satellite communication and ITS applications.

Effective structure of a push-push oscillator using a hair-pin resonator for K-band application

In this paper, a K-band push-push oscillator is designed and implemented with the form of series feedback, which has good coupling efficiency and oscillation frequency stability. The oscillator shows the output power of 1.17 dBm, the fundamental frequency suppression of 24.17 dBc at 18.37 GHz, and the phase noise of -100 dBc/Hz at offset frequency of 100 kHz.

The Implementation of Image Enhancement Algorithm Method for SoC

In the world security market, the size of the biometric industry is gradually increasing, of which the fingerprint verification is recognized of its superiority and marketability in terms of relatively low cost, light weight and uneasiness to input bio-information, compared to other biometric method. Fingerprint Recognition Technologies become popular to be used as a representative of biometrics. As all electronics devices are tending to smaller and smaller, people paid more attention to “linear sensor” method. The most important factor for securing the reliable Fingerprint Recognition Technology is pursuing upgrading the enhancement of the captured fingerprint image from sensors.