On the Effects of Disturbing the Symmetry of a Microstrip Rhombic Resonator

The introduction of a narrow transverse slit or a notch in one of the arms of a symmetrically coupled microstrip rhombic resonator disturbs its symmetry and results in frequency splitting. The latter occurs at odd and even resonant frequencies of the resonator. However, when the sum of the tilt angle ¿ and the angle ¿ defining the position of the notch is equal to 90°, then resonance splitting disappears at the even resonant frequencies. Practical work carried out confirms these theoretical predictions.