An Archimedean Spiral Antenna for Generation of Tunable Angular Momentum Wave

Abstract

In this paper, an Archimedean spiral antenna has been developed to flexibly radiate orbital angular momentum (OAM) wave with tunable modes. The operation mechanism for generation of the OAM wave is elaborated in terms of phases of the currents flowing on the spiral arm of the Archimedean structure. Two pairs of feeding probes are introduced to excite the Archimedean spiral antenna. With the signals with different phase differences fed into the spiral antenna, the OAM waves with the modes of l=±1, l=±2, and their all mixed modes are radiated, respectively. Simulated and measured results are given to demonstrate that the proposed Archimedean spiral antenna radiates the tunable OAM waves from the sole mode to the mixed four modes in an overlapped band of 5~6 GHz.INDEX TERMS Archimedean spiral, orbital angular momentum (OAM), tunable, mixed four modes.

A general N ‐arm Archimedean spiral antenna synthesis method for broadband multiple orbital angular momentums generation

“…Since the bandwidth and the number of OAM modes influence communication capacity and imaging resolution, it is of great importance to the generation of broadband multiple OAMs for many practical applications. In the microwave region, plenty of novel antennas are designed for OAM generation, such as the single microwave patch antenna [7, 8], metasurface [9, 10], phased antenna array [11, 12], ring‐slot structure antenna [13, 14], helix antenna [15, 16] and planar spiral antenna [17–22]. Among these antennas, a single microwave patch antenna may only generate OAM in a narrowband [7, 8].…”

“…However, the radiation mechanism of single‐arm ASA is only explained [17]. Then, other researchers also proposed several spiral antennas to generate multiple OAMs at the same frequency [18], broadband multiple OAMs [19–21] and tunable OAMs [22]. Nevertheless, the mechanism for the generation of broadband multiple OAMs by N ‐arm ASA is still not clear, and the relationships among the number of arms, the bandwidth and the OAM modes have not been explained at all.…”

A New Observation in Spiral and Curl Antenna Configurations above the Ground Plane

“…Spiral [5] and curl [6] antennas are also known as CP elements [7,8]. These are nonresonant antennas, and are excited with a single feed.…”

Multi-function terahertz wave manipulation utilizing Fourier convolution operation metasurface

“…[15][16][17][18][19] At present, most of the orbital angular momentum research is focused on the generation of vortex beams from microwave to optical wave regimes. [20][21][22][23][24][25] But, there are few literature on terahertz vortex beam generator. Furthermore, metasurface combined with Fourier convolution becomes more meaningful for terahertz vortex beam regulation.…”