60-GHz LTCC Differential-Fed Patch Antenna Array With High Gain by Using Soft-Surface Structures

• Published in: IEEE transactions on antennas and propagation Vol. 65; no. 1; pp. 206 - 216
• Main Authors: Jin, Huayan, Che, Wenquan, Chin, Kuo-Sheng, Shen, Guangxu, Yang, Wanchen, Xue, Quan
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 60 GHz; Antenna arrays; Antenna gain; Antenna radiation patterns; Antennas; Cross polarization; differential-fed structure; Dispersion; Equivalent circuits; High gain; Insertion loss; Integrated circuit modeling; low cross polarization; Low temperature; low-temperature cofired ceramic (LTCC); Patch antennas; Periodic structures; Radiation; soft-surface structure; Substrate integrated waveguides; Surface structure; surface wave suppression; Surface waves; wide bandwidth
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2016.2631078

This paper presents a 60-GHz 4 × 4 differential -fed patch antenna array using low-temperature cofired ceramic (LTCC) process. Wideband patch with L-shaped feeding scheme is adopted as antenna element, while differential substrate integrated waveguide feeding network with low insertion loss is applied for the integration of antenna array. The differentialfed structure improves the symmetry of radiation patterns and reduces the cross-polarization level significantly. To further suppress the surface wave and improve the gain of the antenna array, one kind of soft surface structure is proposed. The equivalent circuit model of the soft surface is developed for calculating its dispersion diagram and analyzing stopband characteristics. The simulated results indicate that the antenna gain enhancement can be up to 2 dB because of the proposed soft surface. For demonstration, one prototype using LTCC process is fabricated and measured. The measured 10-dB impedance bandwidth of the antenna array is 11.7%. The measured antenna peak gain of 18.62 dBi at 61.5 GHz and symmetrical radiation patterns with a low cross polarization of -25 dB across the whole operating frequency are achieved.