Millimeter-Wave Microstrip Comb-Line Antenna Using Reflection-Canceling Slit Structure

• Published in: IEEE transactions on antennas and propagation Vol. 59; no. 2; pp. 398 - 406
• Main Authors: Hayashi, Y, Sakakibara, K, Nanjo, M, Sugawa, S, Kikuma, N, Hirayama, H
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Applied sciences; Array antenna; Arrays; Beams (radiation); comb-line antenna; Couplings; Exact sciences and technology; Feasibility; Feeding; Linear arrays; Microstrip; microstrip antenna; Microstrip antenna arrays; Microstrip antennas; millimeter-wave; Propagation losses; Radiocommunications; Reflection; Resonant frequency; Slits; Telecommunications; Telecommunications and information theory; Wavelengths; Performance evaluation; comb-line antenna; Return loss; microstrip antenna; Travelling wave; millimeter-wave; Wave reflection; Microstrip line; Millimetric wave; Array antenna; Accuracy; Linear antenna; Microstrip antennas; On line processing; Antenna feeds; Radiation pattern; Feasibility; Linear antenna arrays; Antenna array
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2010.2096180

A microstrip comb-line antenna is developed in the millimeter-wave band. When the element spacing is one guide wavelength for the broadside beam in the traveling-wave excitation, reflections from all the radiating elements are synthesized in phase. Therefore, the return loss increases significantly. Furthermore, re-radiation from elements due to the reflection wave degrades the design accuracy for the required radiation pattern. We propose the way to improve the reflection characteristic of the antenna with arbitrary beam directions including strictly a broadside direction. To suppress the reflection, we propose a reflection-canceling slit structure installed on the feeding line around each radiating element. A 27-element linear array antenna with a broadside beam is developed at 76.5 GHz. To confirm the feasibility of the simple design procedure, the performance is evaluated through the measurement in the millimeter-wave band.