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 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 0.34λ
₀
× 0.13λ
₀
0.19λ
₀
The antenna can achieve good matching within the frequency range of 14.4 to 16.0 GHz.