• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.196-203
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• 2006

An air-gap type FBAR was designed using Leach equivalent model for analyzing a vertical structure of the FBAR. For the top electrode, Pt, and the bottom electrode, Au, of $1.2{\mu}m$ thickness and the piezoelectric of 0.8,urn thickness, the resonance and anti-resonance occurred at 2.401 GHz and 2.460 GHz, respectively. $S_{11}$ was increased and $S_{21}$ was decreased as the resonance area of FBAR was widened. We observed the characteristics of insertion loss, bandwidth and out-of-band rejection of ladder-type FBAR BPF by changing resonance areas of series and shunt resonators and by adding stages. As the resonance area of series resonator was increased, insertion loss was improved but out-of-band rejection was degraded. And as the resonance area of shunt resonator was increased, insertion loss was degraded a little but out-of-band rejection was improved even without adding stages. We, also, changed the shape of the resonance area from square shape to rectangle shape to examine the effects of the resonator shape on the characteristics of the BPF. The best performances were observed when the sizes of series and shunt resonator are $150{\mu}m{\times}l50{\mu}m\;and\;5{\mu}m{\times}50{\mu}m$, respectively. Out-of-band rejection was improved about 10dB and bandwidth was broadened from 30MHz to 100MHz utilizing inductor tuning on $2{\times}2\;and\; 4{\times}2$ ladder-type BPFs.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.626-632
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• 2017

This paper describes a high power amplifier combining eight low power amplifiers using a radial power combiner with low insertion loss. The radial power combiner is a non-resonant type combiner with 8 input ports and is implemented by microstrip transmission line. The combiner characteristics designed at operating frequency of 1.045 GHz have an insertion loss of 0.7 dB and a return loss of more than 12 dB. Also, the low power amplifier used was designed with AFT27S010NT1 transistor and designed to satisfy the same gain, phase and constant output characteristic at operating frequency. The high power amplifier, which combiners the radial power combiner and the drive amplifier of 8 W output by driving low power amplifiers obtained the output characteristic of 33 W at operating frequency of 1.045 GHz. Also, the change of the output characteristic of the amplifier using the radial combiner was graceful degradation when the low power amplifier failed one by one.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.470-476
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• 2008

In this paper, we describe the cause of TDMA noise and distinction method of TDMA noise source in a GSM mobile phone. The causes of TDMA noise are composed of RF(Radio Frequency) energy coupling and low frequency energy coupling by burst ripple. We propose the distinction method of TDMA noise source from output(TDMA noise measurement) and frequency response of a system(audio path). Especially we propose a method of insertion loss($S_{21}$) analysis and the improvement method for RF energy coupling. Capacitor(40 pF) is a solution to reduce RF energy coupling and therefore TDMA noise was reduced by 10 dB.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.174-179
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• 2013

This paper presents a capacitor loaded tunable bandpass chip filter using multiple split ring resonators (MSRRs) with two transmission zeros. To obtain high selectivity and minimize the chip size, asymmetric feed lines are adopted to make a pair of transmission zeros located on each side of passband. Compared with conventional filters using cross-coupling or source-load coupling techniques, the proposed filter uses only two resonators to achieve high selectivity through a pair of transmission zeros. In order to optimize selectivity and sensitivity (insertion loss) of the filter, the effect of the position of asymmetric feed line on transmission zeros and insertion loss is analyzed. The SOI-CMOS switched capacitor composed of metal-insulator-metal (MIM) capacitor and stacked-FETs is loaded at outer rings of MSRRs to tune passband frequency and handle high power signal up to +30 dBm. By turning on or off the gate of the transistors, the passband frequency can be shifted from 4GH to 5GHz. The proposed on-chip filter is implemented in 0.18-${\mu}m$ SOI CMOS technology that makes it possible to integrate high-Q passive devices and stacked-FETs. The designed filter shows miniaturized size of only $4mm{\times}2mm$ (i.e., $0.177{\lambda}g{\times}0.088{\lambda}g$), where ${\lambda}g$ denotes the guided wave length of the $50{\Omega}$ microstrip line at center frequency. The measured insertion loss (S21)is about 5.1dB and 6.9dB at 5.4GHz and 4.5GHz, respectively. The designed filter shows out-of-band rejection greater than 20dB at 500MHz offset from center frequency.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.12
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• pp.14-21
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• 1997

This study was conducte dto fabricate 2GHz circulator using Ca,Sn substituted UIG(yttrium iron garnet)ceramics. When the electric, magnetic and microwave properties were measured in Ca, Sn substituted YIG, the measured perimittivity and perfmeability in microwave frequencies were 16.25, 0.8964. For $Y_{2.4}$C $a_{0.3}$A $n_{0.3}$F $e_{3.5}$A $l_{1.5}$ $O_{12}$ garnet ceramics sintered at 1400.deg. C, the ferrimagnetic resonance line width (.DELTA.H) at 10GHz was 53 Oe and saturation magnetization was 375G. The strip-line circulator was simulated with 3-D FEM (finite element method) software and designed at the center frequency of 2GHz. The fabricated strip-line junction circulator using above YIG ceramics had insertion loss of 1.271dB, return loss of 23.843dB, isolation of 21.751dB at the center frequency 1.855GHz.z.z.z.z.z.z.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.128-134
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• 2009

In this paper, we propose a new lumped Wilkinson power divider which is designed to have lower quality-factors in the impedance transformation. Therefore, it can provide wider bandwidth than the conventional one. Moreover, the proposed power divider consists of fewer number of elements so that the circuit size can be further reduced. Simulation results show that the proposed lumped power divider allows a 50% wider bandwidth in the return loss and isolation performance. The conventional and new Wilkinson power was designed and fabricated based on the derived equations at 2.0 GHz. In the measurement, the proposed divider achieved a good performance with an input return loss ($S_{11}$) of -23.0 dB, an isolation ($S_{23}$) of -29.0 dB and an insertion loss ($S_{21}$) of -3.12 dB at the design frequency with wider bandwidth than the conventional one.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.94-98
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• 2023

In the case of high-speed data transmission on high multilayer boards, signal coherence is a problem, especially due to the via hole, and a solution to improve return loss or insertion loss by applying a back drill to the via hole is being proposed. In this paper, Near-Field Electromagnetic measurements were made on a high multilayer board to determine how the presence or absence of back drill affects signal consistency. For this purpose, we used a signal generator, spectrum analyzer, and EMC scanner on a test board to determine if it is possible to distinguish between areas with and without back drill in the via holes of the stubs on the board. Also, we analyzed the measured value of S11, S21 and EMC etc. for how much it improves the signal attenuation of the stub with back drill. Through this, we knew that less electromagnetic waves are generated the stub via with back drill. At future research, we will analyze how much it improves the signal loss and electromagnetic waves due to the depth of back drill.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.53-58
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• 2008

In this study, we fabricated embedded IC (Double Pole Double throw switch chip) polymer substrate and evaluate it for 2.4 GHz WiFi application. The switch chips were laminated using FR4 and ABF(Ajinomoto build up film) as dielectric layer. The embedded DPDT chip substrate were interconnected by laser via and Cu pattern plating process. DSC(Differenntial Scanning Calorimetry) analysis and SEM image was employed to calculate the amount of curing and examine surface roughness for optimization of chip embedding process. ABF showed maximum peel strength with Cu layer when the procuring was $80\sim90%$ completed and DPDT chip was laminated in a polymer substrate without void. An embedded chip substrate and wire-bonded chip on substrate were designed and fabricated. The characteristics of two modules were measured by s-parameters (S11; return loss and S21; insertion loss). Insertion loss is less than 0.55 dB in two presented embedded chip board and wire-bonded chip board. Return loss of an embedded chip board is better than 25 dB up to 6 GHz frequency range, whereas return loss of wire-bonding chip board is worse than 20 dB above 2.4 GHz frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.235-235
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• 2009

This paper describes the influence of a polycrystalline (poly) 3C-SiC buffer layer on the surface acoustic wave (SAW) properties of poly aluminum nitride (AlN) thin films by comparing the center frequency, insertion loss, the electromechanical coupling coefficient ($k^2$), andthetemperaturecoefficientoffrequency(TCF) of an IDT/AlN/3C-SiC structure with those of an IDT/AlN/Si structure, The poly-AlN thin films with an (0002)-preferred orientation were deposited on a silicon (Si) substrate using a pulsed reactive magnetron sputtering system. Results show that the insertion loss (21.92 dB) and TCF (-18 ppm/$^{\circ}C$) of the IDT/AlN/3C-SiC structure were improved by a closely matched coefficient of thermal expansion (CTE) and small lattice mismatch (1 %) between the AlN and 3C-SiC. However, a drawback is that the $k^2(0.79%)$ and SAW velocity(5020m/s) of the AlN/3C-SiC SAW device were reduced by appearing in some non-(0002)AlN planes such as the (10 $\bar{1}$ 2) and (10 $\bar{1}$ 3) AlN planes in the AlN/SiC film. Although disadvantages were shown to exist, the use of the AlN/3C-SiC structure for SAW applications at high temperatures is possible. The characteristics of the AlN thin films were also evaluated using FT-IR spectra, XRD, and AFM images.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.42-46
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• 2014

In this paper, a coil typed electromagnetic band gap (EBG) structure to be inserted in the printed circuit board (PCB) inner layer in order to stabilize the PCB power line is proposed and implemented for global-navigation satellite service (GNSS) with the bandwidth from 1.55GHz to 1.81GHz. From the measurement result of the PCB board including EBG structure, the insertion loss(S21) was measured below about -50dB. From these results, it is expected that the stabilization of power delivery network (PDN) structure in the PCB circuit design should be improved and the preparation to EMI will be effective.