• Journal of electromagnetic engineering and science
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• v.5 no.4
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• pp.208-212
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• 2005

In this paper, we introduced a band-pass filter employed the PBG structure and the aperture on the ground together. The harmonics of band pass filter have been suppressed by employing the PBG structure and the bandwidth of it has been broadened by using the aperture on the ground. The designed PBG cells have three different sizes. The largest cells, the middle cells, and the smallest cells have suppressed the multiple of second harmonics, the multiple of third harmonics, and the multiple of fifth harmonics, respectively. The center frequency has been 2.18 GHz. The bandwidth has been increased from 230 MHz up to 310 MHz(80 MHz, about $35\%$) by the aperture and the ripple characteristics in passband have been improved and the harmonic frequencies have been suppressed about 30 dB by the PBG.

• ETRI Journal
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• v.29 no.4
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• pp.533-535
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• 2007

For the purpose of decreasing intermodulation distortion, a new multi-harmonic suppression band-pass filter based on a microstrip radial stub is studied. Compared with traditional resonator filters, the new filter can suppress the second, third, and even fourth harmonics directly. The dimension of the filter is about $0.3\;{\lambda}_{g^0}{\times}0.13\;{\lambda}_{g^0}$ (${\lambda}_{g^0}$ is the guiding wavelength at the resonant frequency). Only one gap was introduced, so lower insertion loss can be obtained. Basic agreement between the measured and simulated results has been achieved.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.42-46
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• 2014

A modified network to suppress the nth harmonics in a Wilkinson power divider is presented. The solution has been found by adding transmission lines, whose electrical lengths are determined by using the suppression terms, between two transformers of the traditional design. Experimental results show the second and third harmonics levels achieved are -45.3 and -46.4 dB, respectively, while the performance of the power divider at the fundamental frequency is maintained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.845-851
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• 2006

Folded lines are applied to design a compact microstrip ring hybrid. Using the proposed structure we achieve both significant size reduction and good harmonic suppression with the same results of conventional ring hybrid at 2.41 GHz. Including the third harmonic frequency, up to 11 GHz band harmonics are suppressed to -20 dB. The size of the proposed ring-hybrid is reduced to one forth of the conventional ring hybrid. The measured frequency responses agree well with simulated ones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.3
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• pp.151-158
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• 2018

This paper proposes a new design method for narrow bandpass filters using two cascaded hairpin step impedance resonators (SIRs) with wideband harmonic suppression. The proposed bandpass filter utilizes a suspended strip line (SSL) to maximize the characteristic impedance ratio, thereby maximizing the harmonic suppression bandwidth. As an example of the proposed design method, the SSL bandpass filter with a center frequency of $f_0=1.4GHz$ and fractional bandwidth of 5 % was implemented, and proved to suppress harmonics up to $7.5f_0$ with a passband insertion loss of approximately -0.9 dB. This result implies that the proposed SSL narrow bandpass filter (NBPF) can suppress the harmonic bandwidth more than two times as compared with the filter design on a microstrip line (MSL).

• Journal of Navigation and Port Research
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• v.29 no.7
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• pp.615-618
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• 2005

A new structure of the Wilkinson power divider that can suppress multiple harmonics output is presented The power divider consists of T-type or $\pi$-type capacitive loads and shunt resistors. Experimental results show that this power divider suppresses the second and the third harmonic components to less than -38dB, while maintaining the characteristics of a conventional Wilkinson power divider, featuring an equal power split, a simultaneous impedance matching at all ports and a good isolation between output ports.

• ETRI Journal
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• v.28 no.4
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• pp.529-532
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• 2006

This letter describes a compact printed helical resonator and its application to a microwave oscillator circuit implemented in coplanar waveguide (CPW) technology. The high quality (Q)-factor and spurious-free characteristic of the resonator contribute to the phase noise reduction and the harmonic suppression of the resulting oscillator circuit, respectively. The designed resonator showed a loaded Q-factor of 180 in a chip area of only 40% of the corresponding miniaturized hairpin resonator without any spurious resonances. The fully planar oscillator incorporated with this resonator showed an additional phase noise reduction of 10.5 dB at a 1 MHz offset and a second harmonic suppression enhancement of 6 dB when compared to those of a conventional CPW oscillator without the planar helical resonator structure.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.293-297
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• 2009

In this thesis, design of a VCO(Voltage controlled Oscillator) with a novel tuning mechanism is presented for the Radar system. This circuit, the 9.5 GHz oscillator is designed and implemented by restructuring microstrip resonator to raise Q value and to require a wide frequency tuning range. This product is fabricated on 2.6 Teflon substrate and device is NE722S01. In this paper, The new microstrip resonator VCO is proposed to achieve the characteristic of a wide frequency tuning range. This microstrip resonator VCO shows the phase noise characteristic of -108.3 dBc/Hz at 1 MHz offset from the fundamental frequency, the output power of 5.7 dBm and the second harmonic suppression of -38 dBc for the VCO are obtained. The manufacture VCO shows a frequency tuning range of 193.8 MHz. The proposed micro trip resonator VCO can be used for X-band Radar System with required tuning range.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.145-149
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• 2003

The parallel feedback dielectric resonator oscillator (DRO) which is applicable to satellite communications and broadcasting has been investigated. In the design of oscillator, the phase noise is important parameter. In this paper, The proposed oscillator has good phase noise level because it suppressed harmonics. Measurement show the fabricated oscillator is output power of about 9 dBm at fundamental frequency of 12.0 GHz and fundamental frequency suppression of -47.5 dBc. The phase noise level is about -110 dBc/Hz at 100 KHz offset frequency.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.72-76
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• 2003

In this paper, active frequency doubler with broadband characteristics and unconditional stability from 6GHz to 12GHz was designed and fabricated using PHEMT. The designed frequency multiplier has a bias point near pinch-off and a proposed RC circuit between bias line and input matching network for the improvement of stability. With 0dBm input power, second harmonic of 1.7dBm at 12GHz, - 27.5dBc suppression of 6GHz fundamental, -18dBc suppression of 18GHz 3rd harmonic and the output bandwidth of 1.8GHz have been measured.