2–18 GHz Conformal Low-Profile Log-Periodic Array on a Cylindrical Conductor

This paper presents a conformal log-periodic array covering an ultra-wideband of 2–18 GHz. It employs monopoles of different heights for the high band, top-hat monopoles for the middle band, and folded top-hat monopoles for the low band. The top hats help to achieve a low profile of the monopoles while the folding is to maintain a good input resistance at the low band. A meandering microstrip line on the bottom is used to feed the array. The proposed antenna is mounted on a conducting cylindrical surface with all the top hats conformal and aligned to the outline of the cylinder. A prototype is fabricated and tested. Measured results show that an impedance bandwidth from 2 to 18.3 GHz (9.15:1) for VSWR < 2 is obtained. Over the same band, the measured gain is better than 7.2 dBi. The antenna has a very low profile of $0.053~\lambda _{L}$ at the lowest operating frequency, which should be useful in many communication systems such as missile and airborne applications.

[1]  Heinrich Foltz,et al.  Closed-form lumped element models for folded, disk-loaded monopoles , 2002, IEEE Antennas and Propagation Society International Symposium (IEEE Cat. No.02CH37313).

[2]  Zhongxiang Shen,et al.  Low-Profile Top-Hat Monopole Yagi Antenna for End-Fire Radiation , 2015, IEEE Transactions on Antennas and Propagation.

[3]  Zhongxiang Shen,et al.  Wideband Flush-Mounted Surface Wave Antenna of Very Low Profile , 2015, IEEE Transactions on Antennas and Propagation.

[4]  R. Carrel,et al.  ANALYSIS AND DESIGN OF THE LOG-PERIODIC DIPOLE ANTENNA , 1961 .

[5]  Wideband and low-profile end-fire antennas mountable on metallic platforms , 2015, 2015 IEEE Conference on Antenna Measurements & Applications (CAMA).

[6]  Zhongxiang Shen,et al.  Wideband and Low-Profile Monocone Quasi-Yagi Antenna for Endfire Radiation , 2017, IEEE Antennas and Wireless Propagation Letters.

[7]  Zhongxiang Shen,et al.  Wideband and Low-Profile H-Plane Ridged SIW Horn Antenna Mounted on a Large Conducting Plane , 2014, IEEE Transactions on Antennas and Propagation.

[8]  J. Eberle,et al.  The flared slot: A moderately directive flush-mounted broad-band antenna , 1960 .

[9]  Qiu Jing-hui,et al.  A novel miniaturized ultra wideband log-periodic antenna , 2010, 2010 5th International Confernce on Ultrawideband and Ultrashort Impulse Signals.

[10]  Sungkyun Lim,et al.  Size reduction of the Log-Periodic Dipole Array , 2013, 2013 IEEE Antennas and Propagation Society International Symposium (APSURSI).

[11]  R. Hansen,et al.  Scanning surface wave antennas--Oblique surface waves over a corrugated conductor , 1958 .

[12]  Hui Zhang,et al.  A small and wideband second order Koch-fractal log-periodic antenna , 2013, 2013 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference.

[13]  Zhongxiang Shen,et al.  Low-Profile Log-Periodic Monopole Array , 2015, IEEE Transactions on Antennas and Propagation.

[14]  P. Green,et al.  50 Ω Log-periodic monopole array with modulated-impedance microstrip feeder , 1974 .

[15]  E. W. Seeley.  An experimental study of the disk-loaded folded monopole , 1956, IRE Transactions on Antennas and Propagation.

[16]  Quan Xue,et al.  Microstrip Magnetic Dipole Yagi Array Antenna With Endfire Radiation and Vertical Polarization , 2013 .

[17]  C. Friedman.  Wide-band matching of a small disk-loaded monopole , 1985 .

[18]  Zhongxiang Shen,et al.  Conformal SIW H-Plane Horn Antenna on a Conducting Cylinder , 2015, IEEE Antennas and Wireless Propagation Letters.