High-Endfire-Gain Dielectric Image Line-Based Periodic Leaky-Wave Antenna With Planar Feeding

A high-endfire-gain periodic leaky-wave antenna (LWA) based on dielectric image line (DIL) and fed by a planar transition is proposed. The unit cell of the periodic DIL consists of two dielectric blocks with different permittivity, and space harmonics (SHs) are then generated. A revised formula for phase constant of the nth space harmonic is introduced for the periodic structure. Although the proposed antenna is grounded, it obtains high endfire gain with a small cross section and experiences a slight deflection beam direction, effectively addressing the issue of conformity between the endfire antenna and metal surfaces. The maximum measured endfire gain is 16 dBi, achieved with a cross-sectional area of 0.34λ₀ × 0.13λ₀ × 19λ₀. The antenna can achieve good matching within the frequency range of 14.4 GHz to 16.0 GHz.