Introduction of a new fractal antenna loaded Sierpinski gasket antenna

November 24, 2022

Radio Frequency Identification (Radio Frequency IdenTIficaTIon, RFID) is an automatic identification technology that emerged in the 1990s. The technology utilizes a contactless approach to obtain target information and communicates bidirectionally with the target information. Due to its contactless working characteristics, it is called the third generation automatic identification technology. An automatic identification system consists of two parts: a reader and an electronic tag. The antenna plays an important role in the reader and the electronic tag. It is an indispensable device for achieving contactless two-way communication between the two. Antennas are used to transmit and receive signals and serve an important role in coupling energy in electronic tag chips. Therefore, the design of the electronic tag antenna directly affects the working distance and range of use of the system.

In the application of RFID systems, the electronic tag antenna needs to be attached to the object to be identified as a status symbol for identifying the object, and due to the diversity of the identified object, people put forward higher requirements for the electronic tag antenna, mainly reflected in the broadband The belt is miniaturized, easy to install and carry, and requires high efficiency of the antenna. Antenna design relies heavily on the frequency of the antenna, and some types of antennas have a wide bandwidth, such as a helical antenna. In this sense, the antenna is embodied in the self-similarity of the fractal antenna. The self-similarity of the fractal antenna is of great significance for the design of the electronic tag antenna.

The fractal antenna is a new type of antenna that applies fractal geometry to the antenna, which is completely different from the traditional European geometric antenna. The height-space self-filling characteristics of the fractal structure can be transformed into miniaturization features of the fractal antenna, such as a Koch fractal antenna, a Hilbert fractal antenna, a Minkinski fractal antenna, and the like. The self-similarity of the fractal structure can be transformed into a multi-band characteristic of the fractal antenna, typically a Sierpinski fractal antenna.

In this paper, a novel fractal antenna-loaded Sierpinski gasket antenna is proposed. Compared with the conventional antenna, this antenna makes full use of the high self-filling property of the new fractal structure and the multi-band characteristics of the Sierpinski fractal antenna, thus realizing a new type. Miniaturized, multi-band fractal antenna.

1 Geometric description of the fractal structure and antenna generation

The antenna structure of the fractal structure is many. In this paper, a two-point format method is used to construct a novel fractal antenna. First define an initial element and a generator element. The initial element gives the framework of the fractal graphic. The generator element gives the construction method of the new fractal antenna. The initial element and generator of this new fractal antenna are shown in Figure 1.

Load Sierpinski pad antenna

The superscript of the symbol in Figure 1 represents the number of iterations, and the subscript represents the coordinate point. Select:

Load Sierpinski pad antenna

Where: k = 1/4 is the width of the fractal recess.

It can be known from the fractal theory that the fractal dimension D of the new type of structure depends on the following equation:

Through the iterative process of the 1st order generator, it is possible to perform the iteration again to obtain the 2nd and 3rd order generators. Although this new fractal curve has the same iterative characteristics and spatial filling characteristics as the Koch fractal structure, fractal iteration is impossible in practice without limit iteration. It is found that this new curve has a limit value in reducing the resonant frequency. Performance above 5th order is not obvious, here is called the fractal limit. At the same time, due to the limitations of modern manufacturing processes, the general type of antenna is below 5th order.

This new fractal curve has many similarities with the Koch fractal curve. The first-order new fractal curve is 30.18% longer than the first-order Koch curve. The second-order new fractal curve is 1.44 times longer than the Koch curve of the same order, and has fractals. The characteristics of the antenna. It can be explained that the fractal antenna has stronger self-filling capability than the Koch fractal structure, and can be used in the antenna design to realize a longer current effective path, thereby reducing the resonance frequency and realizing miniaturization of the antenna.

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Author:

Ms. Zoe Zhong

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