Method and device for measuring electrical length of radio frequency coaxial cable

Abstract

The invention relates to a method for measuring the electrical length of a radio frequency coaxial cable and a device for realizing the method. The method for measuring the electrical length of a radio frequency coaxial cable comprises the steps of: (S1) providing a measuring device and a coaxial cable to be measured; (S2) calculating a rough electrical length; (S3) cutting the coaxial cable roughly; (S4) calculating a physical length; (S5) cutting the coaxial cable preciously; (S6) verifying the electrical length; and (S7) calculating an accurate electrical length. The device for measuring the electrical length of the radio frequency coaxial cable is characterized by comprising a vector network analyzer, a PC (Personal Computer) and a cable cutting machine, wherein the PC receives data from the vector network analyzer and sends a control signal to the vector network analyzer; and the PC controls the cable cutting machine. The invention provides a high-accuracy method for measuring the electrical length of the radio frequency coaxial cable and the device for implementing the method.

Description

technical field [0001] The invention relates to a method for measuring the electrical length of a radio frequency coaxial cable and a device for realizing the method. Background technique [0002] The ratio of the physical length of the transmission line to the transmission wavelength (in the transmission line). [0003] The transmission speed of radio waves in space is the same as the speed of light, which is close to 300,000 kilometers per second, but the transmission speed in different media is different. When the factory produces cables, because of the manufacturing process, the electrical of each batch of cables There are differences in indicators. For example, two cables with the same physical length have different electrical properties for the same high-frequency signal, so a concept of electrical length is introduced. It reflects the characteristics of the cable to a certain frequency signal within a unit of physical length. Electrical length is a key technical ind...

AI Technical Summary

Problems solved by technology

[0004] Due to the specific differences in the cable manufacturing process, there are differences in the electrical indicators of each batch of cables. This difference is currently controlled within the range of 1%-2% in the industry. Using direct measurement, the measurement accuracy can reach the level of 0.3%-0.5%. For a coaxial cable with a length of 1 meter and an electrical length of 1.40, a measurement error of 0.3% means that a 2GHz signal is transmitted through this cable. After the phase error at 10.08? ? , in the application of RF coaxial cables, some applications are sensitive to phase tolerances, such as the application of a large number of RF coaxial cables in the current 3G mobile communication base station antennas, this tolerance will bring uncertainty in the phase between the antenna elements, resulting in The uncertainty of antenna gain and direction angle will seriously weaken the performance of the antenna

The existing radio frequency coaxial cable electrical length measurement devices all use direct measurement at the set frequency f0, and the measurement error is often more than 0.3%, which leads to the uncertainty of antenna gain and direction angle

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