A dual‐band high‐gain quasi‐Yagi antenna with split‐ring resonators for radio frequency energy harvesting

In this paper, a novel concept on the design of a broadband printed Yagi antenna for S-band wireless communication applications is presented. The proposed antenna exhibits a wide bandwidth (more than 48% fractional bandwidth) operating in the frequency range 2.6 GHz–4.3 GHz. This is achieved by employing an elliptically shaped coupled-directive element, which is wider compared with other elements. Compared with the conventional printed Yagi design, the tightly coupled directive element is placed very close (0.019λ to 0.0299λ) to the microstrip-fed dipole arms. The gain performance is enhanced by placing four additional elliptically shaped directive elements towards the electromagnetic field’s direction of propagation. The overall size of the proposed antenna is 60 mm × 140 mm × 1.6 mm. The proposed antenna is fabricated and its characteristics, such as reflection coefficient, radiation pattern, and gain, are compared with simulation results. Excellent agreement between measured and simulation results is observed.

https://www.mdpi.com/2072-666X/11/11/975/pdf

Design and Development of a Wideband Planar Yagi Antenna Using Tightly Coupled Directive Element.

In this paper, a single zero compensation dipole antenna for WLAN frequency band is designed. The antenna can be suspended above the space and the radiation range can cover the whole space below. The antenna is fed by the parallel transmission lines, and the radiation unit consists of a printed dipole antenna and a Yagi antenna. The printed dipole antenna is printed on both sides of the FR-4 dielectric substrate with relative permittivity of 4.3. The printed dipole antenna adopts complementary symmetry structure to optimize the non-roundness of H plane. The driver arms of the Yagi antenna are printed on both sides of the substrate, while the director and the reflector of the Yagi antenna are located in the dielectric substrate to compensate the zero point of the dipole antenna. The simulation results show that the VSWR of the antenna is less than 2 in the 2.32-2.45 GHz band. The maximum directivity is more than 1.8 dBi in the 2.322.45GHz band. The non-roundness of the H plane of the antennais less than 2dB,which shows good omni-directivity. A zero point in the radiation pattern of the E plane is compensated, and it is -1.68dBi at 2.36GHz,0.62dBi at 2.4GHz and 0.48dBi at 2.44 GHz, respectively, while the other zero point of the E plane remains below -12 dBi in the working frequency range, namely realizing the function of single zero compensation.

Design of a Single Zero Compensation Dipole Antenna

The invention discloses a dipole antenna with single zero point compensation. The dipole antenna comprises a dielectric substrate, and a dipole antenna and a microstrip yagi antenna which are arrangedon the dielectric substrate. According to the dipole antenna, dipole arms are arranged on the front surface and the back surface of the dielectric substrate; the dipole arms on the front surface andthe back surface of the dielectric substrate are connected; the dipole arm on the front surface of the dielectric substrate and the dipole arm on the back surface of the dielectric substrate adopt a double-array symmetrical structure; the dipole antenna can perform omnidirectional radiation on an H surface, and a feed port is led out of the dipole antenna; and the microstrip yagi antenna is used for compensating a radiation zero point of the E surface of the dipole antenna in a strong directivity manner in the direction of a director of the microstrip yagi antenna. The dipole antenna with single zero point compensation can achieve the purposes that the antenna is suspended above the space, and the radiation range covers the periphery and the lower portion of the whole space.

Dipole antenna with single zero point compensation

Characteristic mode (CM) analysis is conducted in this paper to understand the physical aspects of a compact planar quasi-Yagi antenna at the lowest resonant frequency for achieving bandwidth enhancement and electrical size reduction. The quasi-Yagi antenna comprises a microstrip feeding line, a driver dipole and two parasitic strips. The driver dipole is modified by symmetrically adding two capacitive coupling structures, which are connected with the ground plane in the other end, through examining the behavior of the CMs. A capacitor with proper value is adopted in the feeding line for better impedance matching in the higher band. Through the work in this paper, the lowest frequency with VSWR $ is extended to 3.09 GHz from 3.65 GHz with no physical size enlarged. Its bandwidth is enhanced with a ratio of about 3.78: 1.

Planar Printed Quasi-Yagi Antenna Designs Using Characteristic Modes

This paper presents a novel miniaturezation Quasi Yagi-Uda antenna based capacitive loading technique and new layout. In the proposed antenna, the horizontal size of the proposed antenna is reduced by adding vertical metallic strips at the end of the driver and reflector. Meanwhile, the 1/4 wavelength transformer and balun are placed horizontally to reduce the vertical size. In this way, the overall dimensions of the proposed antenna could be decrease without much loss in other performance indicators. Then the parameters of the antenna is optimized by the software HFSS. The measurement results exhibit that the proposed antenna has a good VSWR from 902MHz to 928MHz and its gain is about 5.8dBi at 915MHz. And the overall size of proposed antenna is 110mm∗105mm that is around λ/3 × λ/3 where λ is the wavelength of the centre frequency.

A novel miniaturization Quasi Yagi-Uda antenna

This paper presents a miniaturized broadband Quasi-Yagi antenna which adopt new compact layout and modified bowtie driven dipole. In the proposed antenna, the micro strip feed and λ/4 impedance transformer are placed horizontally to reduce the vertical size. Meanwhile, in order to reduce the horizontal size, the vertical metallic strips are loaded to the end of bowtie driven dipole and ground patch. Compared to the conventional Quasi-Yagi antenna, the overall size of the proposed antennas are reduced about approximately 50%. The measured results show that the impedance bandwidth (reflection coefficient< −10dB) of proposed antenna is 1.16GHz (42.6%) for 2.14–3.3GHz and it has a wide bandwidth about 2.23–3.25GHz with reflection coefficient<-15dB. Moreover, the realized gain is around 4dBi in the operating bandwidth. This antenna can be used for wireless communications and recognitions like WLAN, RFID, WiMAX and LTE.

Wei Tang

Papers

A novel miniaturization Quasi Yagi-Uda antenna

Miniaturized broadband Quasi-Yagi antenna for wireless communication and recognition