Heon Jin Hong

Millimeter-wave delay spread measurement and simulation at LoS urban low-rise environments

Delay spread characteristics in the 28GHz band were measured at line of sight urban environments using narrow beamwidth antennas and simulated using ray-tracing with the same conditions. The channel sounder has 500MHz wide bandwidth at 28GHz, and using swept time delayed cross-correlation technique. The measurement environment is urban low-rise areas. The measurement and simulation results are compared to predict a delay spread with a line of sight condition.

A study on the interference in the digital broadcasting area using same frequency

In digital broadcasting system single frequency network (SFN) technologies are often considered for the efficiency of frequency allotment. In SFN, All the transmitters within the broadcasting service area use the same frequency. In this paper, we discuss the performance and evaluate some coverage criterions for SFN in digital video broadcasting - terrestrial (DVB-T) and on-channel repeater (OCR) in the Advanced Television Systems Committee (ATSC). Also, we propose method and simulation for coverage planning and estimation.

Method for Protection Ratio Calculation between Digital Broadcasting Systems

In this paper, we proposed the method for calculating the Protection Ratio (PR) of the Advanced Television Systems Committee (ATSC) broadcasting system from the Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) broadcasting system through the computational experiment. For this, the transmitter/receiver of the ATSC system and transmitter of the ISDB-T system were modeled. By integrating those, the computational simulator for setting up the PR of the ATSC system from the ISDB-T system was implemented. The ATSC TV signal was regarded as the desired one and the ISDB-T TV signal was regarded as the interfering one. In order to simplify the simulation complexity, it was modeled sending/receiving signals in the Intermediate Frequency (IF) band instead of those in the RF band. And it was assumed that one received signal was considered in the channel modeling and theres no Additive White Gaussian Noise (AWGN). By using the calculated PR value, the coverage prediction considering the interference was performed between the adjacent nations which use the different digital broadcasting system.

A design method of closed ioop resonator filter to reduce size and adjust pole

This paper presents a new design method of closed loop resonator filter by using multiple sub-networks that connects transmission line to capacitor in parallel. This method gives an advantage to reduce the size of closed loop resonator without changing permittivity of printed circuit board (PCB) or resonance characteristics. The value of parallel capacitor is used as a design factor to reduce the size of closed loop resonator. Also, this paper introduces the method of positioning attenuation pole at desired frequency by adjusting impedance ratio between sub-networks. This paper presents the implementation of 2 pole closed loop resonator filter that using the same impedance, 50 ohms, between sub-networks. The filter has 70 % reduction in size by adding parallel Cp=1 pF to the designed close loop filter. Also, the 2 pole closed loop resonator filter was designed by the use of 50 ohms and 54.6 ohms that is impedance between sub-networks, respectively in order to put the attenuation pole at 1.8 GHz and 2.5 GHz.