Kyu-Bok Lee

5.2GHz band 2nd-order band-pass filter using LTCC multi-layer technology

In this article, a new type of 1/4 wavelength stripline resonator is composed one side shorted stripline and loading capacitance, and multi-layer band-pass filter is designed for 5.25GHz band W-LAN using proposed resonator. Because the slow-wave effect of the proposed resonator, length of proposed resonator is reduced for common resonator. And, because first spurious resonant frequency value is grown about fundamental resonant frequency, a miniaturized band-pass filter with wide upper stopband can be designed. Designed filter is fabricated using LTCC multi-layer process, and total filter size is 3.2mm /spl times/ 1.6mm /spl times/ 0.8mm.

A Design of Motion Detecting Sensor using Microwave

This paper describes the detecting way of something to use microwave control sensor module which contains K band transceiver, antenna and Dopplers radar theory. Specially it use K band high frequency which is high resolution and high speed response. It consists of gunn oscillator, schottky diode mixer, patch antenna , IF amplifier, power supply and micom. Major technical specifications are detection area is 13 ft(W) 6.5 ft(D) and tilt angle is -30 to +30 lateral. Doppler sensor are used in industrial control applications, such as counting objects moving on conveyor belt, measuring vibration in machine parts or measuring levels of liquid products, etc. Another major use is for automatic door openers for public buildings.

Design of Miniaturized Symmetric Microstrip DC Block

This paper suggests DC blocks that have the length of one-eighth wavelength. The miniaturized dc block is completed by that gap of coupled line is reduced to increase an amount of coupling. These dc blocks not only suppress harmonics but also their sizes are smaller than general dc blocks. To verify performance of the miniaturized dc blocks, several dc blocks are designed and fabricated. These dc blocks are applied in PLDRO operating at 6.3 GHz.

Design of K-band Gunn oscillator

This paper describes oscillator using an Gunn diode at 24 GHz. The oscillator consists of a waveguide cavity and tunning rod that can control frequency and power. In this paper, we choose waveguide type, waveguide iris-coupled cavities are the most common types used at microwave through millimeterwave frequencies. Iris-coupled cavities have the highest Q and best frequency stability. This oscillator has the power of 1dBm and the phase noise of 90dBc at 100kHz offset, stability of 1MHz//spl deg/C. This oscillator can use motion sensing applications, or microwave Doppler module.

CPW-fed compact flexible antenna based on a zeroth-order resonator

This paper proposes a flexible antenna based on a zeroth-order resonator. The flexible antenna is fabricated on liquid crystal polymer substrate with a thickness of 100 um. The antenna operates at 3.18 GHz as zeroth-order mode and its size is 30mm * 30 mm. The return losses of the proposed antenna are almost invariant while it is bent from −90 degree to +90 degree.

Design of Wideband Microstrip Patch Antenna

In this paper, a wideband microstrip patch antenna fed by L-strip structure for the K-PCS (Korea PCS, 1750-1850 MHz) and W-CDMA (1920-2170 MHz) broad-band is presented. A two-element array fed by L-strip structure is also proposed. Both the antennas have stable radiation patterns across the passband. The impedance bandwidth(VSWR<1.5) is over 31% (615 MHz) of the center frequency. Moreover, both the antennas have about 7 dBi average gain.