Under normal circumstances, when the coaxial cable transmits data signals, it will continuously lose the signal, which will cause the signal amplitude to decrease after reaching the end point, and sometimes it will not meet the normal working requirements. The factors that affect signal loss involve resistance loss, dielectric loss, mismatch loss, and leakage loss. Let us do a systematic analysis of these loss factors. I believe you will have a deeper understanding after reading. The coaxial cable signal is lost.
Resistance loss is the consumption of signal energy by the eddy current caused by the DC resistance of the cable and the high-frequency induction of the conductor. The resistance value is related to the raw materials and production processes used in the cable. At the same time, it will change with the change of the transmission frequency, because the conductor has a skin effect in the transmission of AC signals. As the frequency increases, the effective resistance will continue to increase.
2. Dielectric loss
Dielectric loss is the signal loss of the dielectric (insulator) between the center conductor and the outer conductor of the coaxial cable. An important parameter for measuring dielectrics is the dielectric constant. It refers to the ratio of the capacitance when a substance is used as the dielectric in the same capacitor to the capacitance when it is vacuum, which is called the "dielectric constant" of the substance. The dielectric constant usually changes with temperature and the frequency of electromagnetic waves propagating in the medium.
3. Mismatch loss
The mismatch loss is mainly related to the physical structure of the coaxial cable. If the design and production of the coaxial cable cause the cable to deviate from the nominal impedance or the cable impedance is not symmetrical, it will cause signal mismatch loss. Excessive bending, deformation, damage and water ingress of the cable caused by the construction will also cause mismatch loss.
4. Leakage loss
Leakage loss is the signal radiated from the braided gap of the cable shield. It also causes energy loss during signal transmission. It is a problem that cannot be ignored in high-frequency transmission. Therefore, the braiding coverage of the cable cannot be too low.
The analysis of the signal loss of the connector coaxial cable is introduced here. In short, the DC resistance of the cable only plays a major role in the signal attenuation at low frequencies; at high frequencies, the signal attenuation is mainly caused by the skin effect and dielectric loss. Decided. As the frequency of the coaxial cable increases, the signal attenuation increases exponentially. Therefore, the transmission loss of the cable is important to consider high-frequency loss. Of course, in addition to the design, production and processing of the cable, improper construction during use will also have a significant impact on the normal use of the cable.