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A dipole in such a uniform field may twist and oscillate, but receives no overall net force with no linear acceleration of the dipole. The dipole twists to align with the external field. However, in a non-uniform electric field a dipole may indeed receive a net force since the force on one end of the dipole no longer balances that on the other end.
When so loaded the antenna presents a pure resistance to the transmission line, preventing energy from being reflected. The loading coil is often placed at the base of the antenna, between it and the transmission line ( base loading ), but for more efficient radiation, it is sometimes inserted near the midpoint of the antenna element ( center ...
A similar parameter exists to relate the magnitude of the induced dipole moment p of an individual molecule to the local electric field E that induced the dipole. This parameter is the molecular polarizability ( α ), and the dipole moment resulting from the local electric field E local is given by: p = ε 0 α E local {\displaystyle \mathbf {p ...
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal n̂, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
The linear electric polarizability in isotropic media is defined as the ratio of the induced dipole moment of an atom to the electric field that produces this dipole moment. [ 5 ] Therefore, the dipole moment is:
Dipole gain is the ratio of the power density received from the antenna in the direction of its maximum radiation to the power density , received from a lossless half-wave dipole antenna in the direction of its maximum radiation = , The decibel gain relative to a dipole (dB d) is given by = ( , )
The linear molecule CO 2 has a zero dipole as the two bond dipoles cancel. Potassium bromide (KBr) has one of the highest dipole moments because it is an ionic compound that exists as a molecule in the gas phase. The bent molecule H 2 O has a net dipole. The two bond dipoles do not cancel.
An amplifier operating under linear (small signal) conditions is a good example of a non-reciprocal network and a matched attenuator is an example of a reciprocal network. In the following cases we will assume that the input and output connections are to ports 1 and 2 respectively which is the most common convention.