Design of Electrically Small Dipole Antenna Using Orthogonally Attached Split Rings

The design of electrically small dipole antenna is presented in this paper based on self-resonance concept using orthogonally attached split rings. The electrically small dipole is defined as “ka” ≤ 1, where “k” represents the wave number associated with electromagnetic field and “$a$” denotes radius of maximum antenna dimension can be enclosed in an imaginary sphere. A simple dipole antenna is loaded with copper split rings. The dipole current produces electric field which is responsible to induce capacitive effect in near field region below the resonant frequency. After the attachment of split rings, the dipole excites antenna geometry to produce a magnetic field to cancel out the capacitive effect by storing inductive energy. As a result resonant frequency of loaded antenna is significantly reduced compare to simple dipole. The simple dipole is resonated at 3.83GHz whereas split ring loaded antenna is resonated at 1.54GHz. This loaded geometry causes 59.70% reduction in resonate frequency and “ka” value for proposed antenna is 0.58. The comparison for 10dB impedance bandwidth in between orthogonally attached split rings antenna and simple dipole antenna is 18.18% and 10.41% respectively. The proposed antenna is also provided good radiation characteristics for both E and H plane. The Ansys HFSS EM solver tool is used to analysis the return loss, resonant frequency, 10dB bandwidth, input impedance, radiation efficiency and radiation characteristics. A prototype antenna is fabricated to validate the simulation results.