RFIC/MMIC Laboratory


RFIC/MMIC Laboratory (Radio Frequency/Monolithic Microwave Integrated Circuits) at Kwangwoon University carries out active research on RF integrated circuit design, microwave integrated circuit design, LED packaging, GaN HEMT based power components design and fabrication, integrated passive device (IPD) technologies, and Hybrid active/passive devices for various wireless applications, for example, DMB tuner,Interference cancelllation system (ICS) of repeater, Ku-band LNB system.
IPD technology is developed in order to achieve lower cost, further miniaturization, and higher performance in microwave devices applied to the front-end modules of wireless communication system. Various kinds of high performance IPDs have been fabricated on a 6 inch GaAs wafer due to the well-developed, low cost passive manufacturing technology. Different kinds of IPDs like baluns, couplers, power dividers, and filters are successfully designed. The fabricated IPDs show a very good RF performance in spite of their small chip size and low cost.
Microwave oscillator was designed, fabricated and characterized using the spurline L and T type slot resonator for C to X band applications. The miniaturized resonator was designed by terminating the slot lines at both ends of the T-structure. The oscillator exhibited better phase noise characteristic due to the high unloaded Q value of miniaturized spurline resonators. The phase noise characteristic is very important in a microwave Oscillator. The feasibility of integrating that slot resonator in various MMIC technologies can also be expected. Stub-loaded compact planar microwave square open-loop (SOP) based bandpass filter (BPF) is designed, simulated, fabricated, measured using SONNET Electromagnetic Tool and Agilent VNA. The internally loaded stubs are open and attached type accommodated inside the square loops. A large coupling coefficient value can be possible in the square open-loop resonator using those loaded stubs. The open loaded-stub is a modified stepped impedance resonator (SIR) structure, and the attached stubs are two similar and rectangular structures. By integrating those stubs into the loops using open gaps and employing direct-connected asymmetrical feeders, the given configuration excites the resonator at 12 GHz resonant frequency.
An advanced manufacturing process is developed for the fabrication of high-quality AlGaN/GaN high electron mobility transistors (HEMTs) on Si (111) and 4H-SiC substrates. Various material and processing approaches, such as double passivation, metal ohmic contact fabrication, post-gate annealing, and SiC back-side source grounding by the physical dicing method, are evaluated in terms of device performance.
Light emitting diodes (LEDs) have been most extensively used in a variety of application such as automotive lighting, LCD displays, outdoor and indoor illuminations, advertisement, decoration and medical equipment. Therefore, LEDs are the best solution of reducing greenhouse gas emission and also could be nature-friendly technology for lighting applications. Generally scientists research LEDs with a longer lifetime, lower power consumption and higher light illumination with compact-size and cost-effective fabrication. A method for fabricating a Si-based packaging platform with a reflector and electrode-guided interconnections is proposed for the packaging component of a high-power LED module. The reflector is fabricated by Ni/Au/Ag-electroplating which is patterned by SU-8 2075 and 4620 negative photo-resistors and LED chip is dissipated directly to the Si body through the large metal-plated platform. This method is suitable for high-efficiency and low-cost LED packaging.

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