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An infinitely long monopole antenna driven by a coaxial cable is revisited. The associated Weber transform and the mode-matching method are used to obtain simple simultaneous equations for the modal coefficients. Computations are performed to illustrate the behavior of current distribution and antenna admittance in terms of antenna geometries.
Jiseong KIM Eakhwan SONG Jeonghyeon CHO Yujeong SHIM Gawon KIM Joungho KIM
Analytical solutions for the frequency-dependent transmission line model parameters of a stranded coaxial cable, which are not trivial due to the complex geometry, are presented and discussed in this paper. A frequency-dependent effective conductor radius of a stranded wire coaxial cable is proposed to estimate the internal impedance using the Bessel function solutions of a solid wire coaxial cable. The performance of the proposed model is verified by electromagnetic field solver simulation and by experimental measurement. The results show that the proposed model successfully calculates the broadband frequency-dependent RLGC model parameters and characteristic impedance of a stranded wire coaxial cable with high accuracy.
A transmission line created by cables adjoined by connectors is influenced by noise from connectors with contact failure, and such noise degrades communication quality. The authors used a model of a connector with increased contact resistance in a coaxial cable and measured the electromagnetic near-field around a cable while changing positions of the model. In this paper, the result shows that the radiated electromagnetic field has no relationship with the position along the cable of a connector with increased contact resistance, when the contact condition of connector, contact resistance value, measurement position, and length of a transmission line are constant.
Kenji INOMATA Takashi HIRAI Yoshio YAMAGUCHI Hiroyoshi YAMADA
This paper presents a target location estimation method that can use a pair of leaky coaxial cables to determine the 2D coordinates of the target. Since convention location techniques using leaky coaxial cables can find a target location along the cable in 1D, they have been unable to locate it in 2D planes. The proposed method enables us to estimate target on a 2D plane using; 1) a beam-forming technique and 2) a reconstruction technique based on Hough transform. Leaky coaxial cables are equipped with numerous slots at regular interval, which can be utilized as antenna arrays that acts both as transmitters and receivers. By completely exploiting this specific characteristic of leaky coaxial cables, we carried out an antenna array analysis that performs in a beam-forming fashion. Simulation and experimental results support the effectiveness of the proposed target location method.
Chih-Hsien LIN Chang-Hsiao TSAI Chih-Ning CHEN Shyh-Jye JOU
In this paper, a multi-Gbps pre-emphasis design methodology and circuits for a 4/2 Pulse Amplitude Modulation (PAM) transmitter of high-speed data serial link over cable are proposed. Theoretically analysis of the total frequency response including pre-emphasis, package, cable loss and termination are first carried out. In order to gain higher data rates without increasing of symbol rate, we use 4 PAM in our system. Then, we propose a pre-emphasis architecture and algorithm that can enlarge the high frequency response so the overall frequency response in the receiver side is uniform within the desired frequency range. The overall circuit is implemented in TSMC 0.18 µm 1P6M 1.8 V CMOS process. A test chip of this transmitter with pre-emphasis, PLL circuit and on-chip termination resistors is implemented by full custom flow to verify the design methodology. The measurement results of 10/5 Gbps (4/2 PAM) are carried out over 5 meter (m) long cable and is in agreement with our analysis and simulation results.
In this paper, leakage of pulses through the outer sheath of a coaxial cable was examined empirically. Corresponding to two kinds of propagation constants, there must be two modes of propagation, which was observed in the experiments. Because of the difference of their propagation speeds, the leak waveform changes the shape as the propagation. It was shown that a ferrite toroidal core works effectively as a suppressor for the noise current, and the cores work more effectively if they are spreadly located over the cable length because the leaking wave increases during the propagation on tha cable. The penetration phenomena of outer EM waves into the cable were also observed. These empirical results revealed that the EM waves which had once got into the cable were hard to remove. So the cores as the noise reduction parts should be set at the nearer point to the EM source.