Novel low profile ultra-wideband capacitance loaded log-periodic monopole array with reduced transverse dimension

作者：He, Huan; Chen, Yikai^*; Yang, Shiwen

来源：IET Microwaves, Antennas and Propagation, 2019, 13(9): 1443-1449.

DOI：10.1049/iet-map.2018.6012

• ultra wideband antennas
• antenna feeds
• impedance matching
• broadband antennas
• electromagnetic wave polarisation
• microstrip lines
• antenna radiation patterns
• monopole antennas
• monopole antenna arrays
• microstrip antenna arrays
• UHF antennas
• low profile ultra-wideband capacitance loaded log-periodic monopole array
• reduced transverse dimension
• low profile log-periodic array
• vertically polarised end-fire radiation patterns
• 22 antenna elements
• conventional monopoles
• high end band

A novel low profile log-periodic array with vertically polarised end-fire radiation patterns is proposed in this study. It totally consists of 22 antenna elements with three different types of monopole antennas. Specifically, conventional monopoles were utilised at the high end band, while monopoles with different types of top-hat loadings were designed for lower frequency band operation. Shorting posts are strategically introduced to maintain a good impedance matching at the lower band. A folded microstrip line is printed on the back side of the ground plane to feed the array. The log-periodic monopole array achieves a very low profile of 0.063 lambda(l), where lambda(l) is the wavelength at the lowest operating frequency in free space. Moreover, the array also exhibits an extremely narrow width of 0.075 lambda(l) in the transverse dimension, which makes the array an attractive candidate for phased array development along the transverse direction. A prototype of the array is fabricated. Measured results show that the array achieves a minimum realised gain of 4.5 dBi across a wide frequency band of 1.19-11.7 GHz (9.83:1).

• 单位
  电子科技大学