EMI extends well beyond the confines of the assembly-under-review. Analysis of radiated emission and radiated susceptibility calls for a review of the properties of antennae. Fortunately, this review allows many simplifying assumptions to be invoked. Section 5.1 provides a brief overview of the textbook analysis of the half-wave dipole and identifies a very significant parameter; when connected to the output of a radio transmitter which is generating a signal at the half-wave frequency, the dipole exhibits the same characteristics as a resistive load. This has been named the `radiation resistance' and its value has been calculated to be 73 Ω.

Chapter Contents:

• 5.1 The half-wave dipole
• 5.1.1 Radiated power
• 5.1.2 Power density
• 5.1.3 Field strength
• 5.1.4 Power received
• 5.2 The virtual conductor
• 5.3 The threat voltage
• 5.4 The threat current
• 5.5 Coupling via the structure
• 5.6 Radiation susceptibility
• 5.7 Radiated emission

Inspec keywords: antenna theory; dipole antennas; electromagnetic interference

Other keywords: half-wave frequency; radiation resistance; assembly-under-review; resistive load; radiated susceptibility analysis; radio transmitter; half-wave dipole antenna; antenna models; EMI; radiated emission analysis; resistance 73 ohm

Subjects: Electromagnetic compatibility and interference; Antenna theory; Single antennas