| Abstrakt: |
This paper proposes a high-frequency (HF) band on an extremely low-profile antenna that can be mounted on the roof of a car. This antenna generates a monopole-like omnidirectional radiation pattern despite the low height of the patch shape (5 cm, 0.0034λ @ 20 MHz). A coil was installed at the edge of the antenna feeding part and the patch to increase the quality factor (Q-factor) and a shorting pin was connected next to the coil to ensure that in-phase current flows through the feeding part and shorting pin. The coil is designed such that the quality coefficient reaches 1,000 considering the mutual inductance and internal resistance. The Q-factor of the antenna is increased by changing the shorting pin to a shorting plate. A quarter-wavelength monopole antenna with a target frequency of 20 MHz is 6 m in length, whereas the proposed antenna height is only 5 cm (0.0034λ @ 20 MHz) and the patch size is 70 cm × 70 cm (0.047 λ×0.047 λ @ 20 MHz), making it easy to install the antenna on the vehicle roof. The gain in the Q-factor of the antenna, calculated using a 3D radio wave simulation software, was −9 dBi, and the gain when it was mounted on the vehicle roof was −2.7 dBi. The power value measured by introducing the antenna showed a star similar to the gain value calculated via simulations. [ABSTRACT FROM AUTHOR] |
