• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.239-244
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• 1997

A hair-pin shaped microstrip-line resonator and a dielectric resonator for injection-locked oscillators have been designed and fabricated for the comparative studying of their characteristics. In general, a commonly used dielectric resonator shows lower phase noise value than hair-pin resonator in the free-running mode. In the injection-locked mode, however, a hair-pin resonator is superior to the dielectric resonator; the wider tuning range, the 22% improved locking bandwidth, the lower noise effect, the short term stability, and the higher power level. The planar structure of a hair-pin shaped microstrip-line resonator will be easily applied to monolithic microwave integrated circuits.

• ETRI Journal
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• v.31 no.3
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• pp.324-326
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• 2009

We present the design of a compact microstrip lowpass filter with a wide stopband which is up to ten times the cutoff frequency. The filter is based on a coupled-line configuration and shunt open stubs. The open stubs create additional transmission zeros, which are used to extend the stopband of the filter without any additional components or cascaded units. A prototype lowpass filter with a 3 dB cutoff frequency of 0.428 GHz and a 15 dB stopband extended up to 4.77 GHz is fabricated to validate the theoretical predictions.

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.11-15
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• 2002

In this paper, we have proposed the new configuration of wideband antenna using CPW fred lines. The proposed antenna has CPW feed lines and U-slot to achieve wade bandwidth with good impedance matching. The use of CPW feed line can decrease the number of substrates. It is compared with the conventional antenna find by a microstrip fled line. The parameters of CPW fred lines were studied by using the quasi-static approximation which is based on the conformal mapping method. The analysis of CPW discontinuities such as the tapered-step structure and the open ended gap were studied by using the quasi-static approximation which is based on the boundary element method. Also, the equivalent circuit model of multi-layer antenna were proposed using the cavity model. Experiment results of the proposed antenna 7how wide-bandwidth characteristics and good radiation patterns in passband.

• ETRI Journal
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• v.32 no.1
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• pp.148-150
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• 2010

This letter presents the design of a compact bandstop filter (BSF) operating at two frequencies. The proposed BSF consists of open-ended stepped impedance resonators (OSIR) and an end-shorted parallel-coupled microstrip line (E-PCML). The OSIRs are used to achieve the impedance-controlled stopband positions. The wide BSF bandwidths are achieved through enhanced coupling of the E-PCML. Explicit design guidelines are derived using a lossless transmission line model. To validate theoretical predictions, a prototype dual-band BSF operating at 900 MHz and 2,100 MHz with fractional bandwidths of 72% and 36%, respectively, is implemented in microstrip.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.4
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• pp.345-352
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• 2004

The radiation impedance of a magnetostatic surface wave excited in a microstrip line haying ferrite film and its dependence on the width of the microstrip line and the height of the ferrite film are calculated by the full-wave moment analysis. The radiation resistance calculated by the full-wave analysis closely agrees with the measured radiation resistance, while that by the magnetostatic approximation greatly differs from the measured result in the higher-frequency region.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.171-176
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• 1997

A hair-pin shaped microstrip-line resonator and dielectric resonator for injection-locked oscillators have been designed and fabricated for the comparative studying of their performances. In general, a commonly used dielectric resonator shows lower phase noise value than hair-pin resonator in the free-running mode. In the injection-locked mode, however, a hair-pin resonator is superior to the dielectric resonator, the wider tuning range, the 22% improved locking bandwidth, the lower noise effect, the short term stability, and the higher power level. The planar structure of a hair-pin shaped microstrip-line resonator will be easily applied to monolithic microwave integrated circuits.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.11
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• pp.1090-1099
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• 2004

In this paper a novel design of equilateral-triangular microstrip antenna using PIN diode fur switching the resonant frequency is presented and experimentally studied. The proposed antenna has changed the resonant frequency by length of spur-lines on the patch, and PIN diodes are utilized to switch the spur-line on and off. The shape of the spur-line is changed according to the on and off states of PIN diode and the equilateral triangular microstrip antenna has different resonant frequencies in accordance with them. The resonant frequency is 1.22 GHz with off states since the surface currents flow the periphery of T shape spur-lines, while the resonant frequency is 1.82 GHz with on states since the surface currents are little effect with the conventional equilateral triangular microstrip antenna. The radiation pattern of the proposed antenna has a good linear polarization with the cross polarization of -20 dB both with on and off states.

• Journal of the Korea Society of Computer and Information
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• v.3 no.3
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• pp.107-112
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• 1998

In this paper, filter designed and produced to use hi-Z low-Z filter which is easy to produce microstrip line and uses space less than used stub filter. This filter has very short electrical length of lines, that is Bl＜$\pi$/4, lowpass prototype series inductor replaced high impedance line section and shunt capacitance replaced low impedance line section. Replaced each section designed microstrip lines and effective permittivity of the given microstrip calculated and each section width and length calculated dna filter used design. Designed filter compared the theory value of touchstone with the experiment value of real produced filter and an analyzed response charictristic.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.861-864
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• 1999

We designed and fabricated microstrip line fed QMSAs(Quarter-Wavelength Microstrip Antenna) for 850〔MHz〕 band on the CGP-500 Copper-clad Laminates substrate (CHUKOH company) with $\varepsilon$$_{r}$＝2.6, H＝1.6〔mm〕( $\pm$0.08), where the width of the radiation patch is identical with that of the ground plane. The resonant frequencies and the return losses were measured by reducing the PSW(Partially Shorted Width) to 0〔mm〕, step by step, when the microstrip line width was 1.47〔mm〕, 2.93〔mm〕and 4.4〔mm〕separately. As a result, a good characterized antenna with a 11% reduced resonant length and a return loss -29.44〔㏈〕 was obtained when the total PSW was in the range of 70% of radiated patch width, compared to the conventional QMSA.A.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.1
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• pp.23-29
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• 1991

In order to improve the radiation characteristics of the microstrip antenna, microstrip array antenna consisting of one center patch fed by a coaxial probe and several patches directly coupled to the E-plane by microstrip line is analyzed. The equivalent circuit of the array antenna is represented by the conventional transmission line and the various parameters, such as the mdicrostrip line length, the patch length and the feed point location are calculated to improve the radiation pattern for 5-patch array antenna which has the equal patch width. The 5-patch array antenna with the radiation pattern which has low sidelobe level and narrow beam width is fabricated and then the measured results are compared with the computed values and the results of the single patch microstrip antenna too.