Compact Omnidirectional Circularly Polarized Antenna Loaded With Complementary V-Shaped Slits

A novel omnidirectional circularly polarized (CP) antenna loaded with complementary V-shaped slits is presented. It is etched on a single-layer substrate with a patch and ground plane on two sides. By arranging the complementary V-shaped slits in the patch and ground plane, horizontally polarized electric field is generated, such that the |<italic>E</italic>_ϕ| = |<italic>E</italic>_θ| and <italic>δ</italic>_θ-<italic>δ</italic>_ϕ = 90° can be realized. Meanwhile, the performance of CP wave is further improved by etching the orthogonal arc slots at the middle of the patch and ground plane. Avoiding additional stub used to generate the horizontally polarized wave, the presented antenna achieves a compact dimension of 0.52λ₀ × 0.52λ₀ × 0.026λ₀ (λ₀ is the wavelength in free space). The realized antenna operates at 5.8 GHz with a bandwidth of 3.5% (5.65–5.85 GHz). Also, it has a peak gain of 1.26 dBic at 5.75 GHz. A good agreement is obtained between the simulated and measured results.