• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.6C
• /
• pp.619-624
• /
• 2002

In this paper, a novel architecture of programmable divider with fifty percent duty cycle output and programmable dividing number has been proposed. Through HSPICE simulation, a 900MHz frequency synthesizer with proposed (sequency divider has designed in a standard 0.25㎛ CMOS technology To verify the operation of proposed frequency divider, a chip had been fabricated using 0.65㎛ 2-poly, 3-metal standard CMOS processing and experimental result shows that the proposed frequency divider works well. The designed voltage controlled oscillator(VCO) has a center frequency of 900MHz a tuning range of $\pm$10%, and a gain of 154HHz/V. The simulated frequency synthesizer performance has a settling time of 1.5$\mu$s, a frequency range from 820MHz to IGHz and power consumption of 70mW at 2.5V power supply voltage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.1 s.116
• /
• pp.1-6
• /
• 2007

This paper presents an equal 3-way planar-type power divider. In conventional 3-way Wilkinson dividers, it has been difficult to realize the circuit because of the crossover of isolation resistors. In the proposed divider, the isolation resistors can be easily attached to the planar structure of the divider. In addition, no phase difference is observed at output ports without extra line compensation because of its symmetric structure. The fabricated 3-way divider has a greatly improved bandwidth by 160 % in $S_{11}$, 22.4 dB, min of isolation, and in phase characteristics between output ports at 2.4 GHz of center frequency from measurement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.5 s.120
• /
• pp.478-485
• /
• 2007

In this paper, an unequal 1:N Wilkinson power divider with adjustable dividing ratio is proposed. The proposed unequal power divider is composed of basic Wilkinson structure. It consists of rectangular-shaped defected ground structure (DGS), isolated island pattern in DGS, and varactor diodes of which capacitance depends on bias voltage. The characteristic impedance value of microstrip line having DGS goes up and down by controlling bias voltage for diodes, and consequently the power dividing ratio(N) is adjusted. The obtained N from measurement is $2.59{\sim}10.4$ which mean the proposed divider has adjustable unequal dividing ratio.

• Journal of Advanced Navigation Technology
• /
• v.25 no.3
• /
• pp.229-235
• /
• 2021

This paper proposes a method of implementing an unequal power divider for high splitting ratios by using transmission lines connected with open and short stubs. The proposed method is an equivalent circuit analysis of a transmission line with an additional port so that it can be converted to an arbitrary impedance in the center of a 2-port transmission line and a 3-port transmission line with an open or short stub connected in parallel to each port. To prove the validity of this method, a Wilkinson power divider with k² = 20 dB splitting ratio and a Gysel power divider with k² = 17 dB splitting ratio were designed at a center frequency of 1 GHz using a 3-port transmission line equivalent circuit. The experimental results of the electrical characteristics are in good agreement with the simulation.

• Journal of Advanced Navigation Technology
• /
• v.26 no.1
• /
• pp.15-21
• /
• 2022

In this paper, we propose a method to implement an unequal power divider with different complex termination impedances for different output power ratios. The proposed method was designed using a matching the terminated complex impedances of the output port using only the transmission line, and presented an isolation circuits to satisfy the isolation characteristic between the terminating complex impedance ports. To prove the feasibility of this method, an unequal power divider with different load complex impedances with a splitting ratio k² = 3 dB and 1.7 dB and an unequal power divider with different complex termination impedances of all ports with a splitting ratio k² = 3 dB was designed at a center frequency of 2 GHz, and it was confirmed that the measured results of the electrical characteristics agree well the simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.4
• /
• pp.417-426
• /
• 2010

This paper describes the 6-way power divider to be used as a feeding structure of the waveguide array antenna generating the plane wave at the near distance. The SMA connector has been connected at the center of the power divider in order to feed the radiating element. The six output ports made of waveguide are positioned on the peripheral of the divider. This paper proposes the method utilizing the inductive post in order to decrease the return loss. The height of the feeding pin, the diameter of the inductive post, and the distance between the feeding pin and inductive post have been investigated, and as a result, the power divider has been optimized. The simulated and measured results show the low return loss of about -40 dB. The calculated and measured transmission coefficients are -7.78 dB and -8.06 dB, respectively. The output power of the six waveguide port show equal-amplitude and equal-phase distribution. Since the power divider proposed in this paper can be expanded to the divider having several output ports, it could be easily applied to the various array antennas.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.2
• /
• pp.253-259
• /
• 2016

This paper introduces a new variable power divider circuit with an arbitrary power division ratio ranging from $1:{\infty}$ to ${\infty}:1$. The proposed power divider circuit consists of one branch-line coupler to be a good input matching characteristic, two variable phase shifters with 90-degree phase variation to be connected two output paths of the branch-line coupler, and one ring-hybrid coupler to combine output signals of two variable phase shifter. The power division ratio between the two output ports of the proposed power divider can be easily controlled by the phase variation of the two phase shifter. The proposed power divider circuit fabricates on laminated RF-35 (h = 20 mil, er=3.5; Taconic) with a center frequency of 2 GHz. The power division ratio of the fabricated prototype varies from about 1:1000 to 5000000:1, with an input reflection characteristic(S11) of below -20 dB, an insertion loss of about -1.0 dB, and an isolation characteristic of below -17 dB between two output ports in the range 1.9-2.1 GHz.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.10
• /
• pp.1409-1415
• /
• 2021

The Gysel divider has the advantage of easily setting the resistor in the circuit. If the line impedance in the Gysel divider is set differently, the input signal can be distributed to the two output ports at various distribution ratios. This paper proposes the Gysel divider that can change the power distribution to 1:3 or 3:1 by changing the line impedance. The impedance change of the line can be implemented by placing a floating copper plate on the bottom of the microstrip-line. When the floating copper plate and the ground plane are connected, the line operates as the microstrip-line, and when the floating copper plate and the ground plane are disconnected, the line operates as the coplanar-line. The proposed Gysel divider was fabricated at the center frequency of 1.5GHz. The fabricated 3:1 Gysel divider has a stable value S₁₁ of below -17dB, S₂₁/S₃₁ of 4.8±0.2dB, S₂₁(to high output port) of -1.39±0.12dB and S₃₁(to low output port) of -6.15±0.08dB over 1.3~1.7GHz.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.2
• /
• pp.177-180
• /
• 2010

Purpose: As PET test came to be covered by the pay system of medical insurance (July 1, 2006) and the needs for it becoming increased for laboratory purpose, it became necessary to purchase expensive medical equipments to solve those problems. However, as most of equipments that are operated by cyclotron are very expensive as to amount from tens of millions up to hundreds of millions of won, it is difficult to purchase those equipments from the point of medical organizations. It may be possible to self manufacture those equipments with least costs if their parts functions that meets the operators demands. The Nuclear Medicine department of National Cancer Center (NCC) is trying to manufacture and use equipments that can be made with least costs, including introducing 2 medical equipments that can improves the operator's works. Materials and Methods: Example 1: Self production of radioisotope($^{18}F$) divider was fabricated. The NCC's Nuclear Medicine department acquired one acrylic panel, seven 3-way valve, tubing etc. that can be found in the market to make the main body of divider in cooperation with biomedical engineering, and placed them inside hot cell, and installed switching box outside of hot cell to make it possible to control them from outside. This main body of divider were placed in radioisotope transfer line that are manufactured in the cyclotron. Example 2: Self production of $^{18}F$-FDG automated divider was fabricated. The NCC's Nuclear Medicine department used cavro pump syringe that consists the main body of divider in cooperation with biomedical engineering, biomedical engineering developed programs that divides a certain amount. $^{18}F$-FDG automated divider is placed inside hot cell, and cable chords were used in the equipment, and then it was connected to PC outside hot cell to make it possible to control the $^{18}F$-FDG automated divider. Results: From the NCC's Nuclear Medicine department tests that were carried out from March, 2007 until now, we found out that radioisotope can be sent to radiopharmaceuticals composite module we want, and from the tests that are carried out at NCC's Nuclear Medicine department using $^{18}F$-FDG automated divider since August, 2009 it was possible to distribute radiopharmaceuticals into vial intended. Conclusion: Through the two examples above, we found out that costs can be reduced by self manufacturing expensive equipments from NCC's cyclotron room with least costs. Also, it decreased radiation exposure dose on workers, and set up problem solving processes in cooperation with lots of parties related.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.07a
• /
• pp.316-316
• /
• 2004