Resonance-Based Reflector and Its Application in Unidirectional Antenna with Low-Profile and Broadband Characteristics for Wireless Applications

• Published in: Sensors (Basel, Switzerland) Vol. 16; no. 12; p. 2092
• Main Authors: Peng, Lin, Xie, Ji-Yang, Sun, Kai, Jiang, Xing, Li, Si-Min
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 09.12.2016; MDPI
• Subjects: Antenna design; Antennas; Broadband; low profile; Phase transformations; Receiving; Reflection; Reflectors; Remote sensors; resonance based reflector; Resonators; Sensors; unidirectional; wireless applications; Wireless communication; Wireless communications; unidirectional; resonance based reflector; low profile; wireless applications; broadband
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s16122092

In this research, the novel concept of a resonance-based reflector (RBR) was proposed, and a ring-shaped RBR was utilized to design a unidirectional antenna with low-profile and broadband characteristics. Research found the ring operates as two half-wavelength ( /2) resonators. Then, the resonance effect transforms the reflection phase of the ring RBR, and achieves a reflection phase of 0° < < 180° in a wide frequency range above the resonance. Then, the in-phase reflection characteristic (-90° < < 90°) can be obtained in the wide frequency band by placing an antenna above the RBR with a distance smaller than /4. Two unidirectional antennas, named Case 1 and Case 2, were designed with the ring-shaped RBRs and bowtie antennas (RBR-BAs). The impedance bandwidths of Case 1 and the Case 2 are 2.04-5.12 GHz (86.3%) and 1.97-5.01 GHz (87.1%), respectively. The front-to-back ratio (FBR, an important parameter to measure the unidirectional radiation) of Case 1 ranges from 5-9.9 dB for frequencies 2.04-2.42 GHz, and the FBR of Case 2 ranges from 5-16 dB for frequencies 2.16-3.15 GHz. The proposed concept of RBR is desirable in wideband unidirectional antenna design, and the designing antennas can be used at the front end of wireless systems-such as indoors communication, remote sensing, and wireless sensor systems-for signal receiving or transmitting.