First, in wireless transmission system, antenna design 40HF120 is particularly important. The quality of antenna directly affects the quality of communication. If the antenna design is not good, it will make the transceiver and receiver can not work properly. The manufacturer of CC2420, TI, has provided some official reference documents for ZigBee antenna design at 2.4 GHz frequency, which mentions two PCB board antenna design schemes, and the customized 2.4 GHz high gain antenna is also a convenient and feasible method.
2. In this paper, inverted F-type PCB antenna and external high-gain velvet are used for different nodes. After a long period of practical development and testing, it is proved that both antennas work stably and fully meet the application requirements. The following explanations are given for the design schemes of the three antennas.
1. Inverted F-type PCB antenna is a kind of antenna. The maximum gain measured in practice can reach +3.3dB. The whole antenna takes up a total area of 25.7mm*7.5mm in the design of PCB board, and this part of PCB board can not be equipped with other devices, and the back of PCB antenna can not be coated with copper. This PCB antenna is relatively simple in design, but it covers a large area. As a kind of omnidirectional antenna, its gain on three planes of XYZ coordinate system is not very different.
2. Another 2,4 GHz PCB antenna design officially provided by TI for small size PCB antenna is actually an inverted F-type board-mounted antenna. It also needs to reserve a special space for PCB board design, and can not lay other components and copper pavement; it is also an omnidirectional antenna.
What is different from the first antenna is that:
It occupies a smaller area of PCB board, only needs 15.2 mm * 5.7 mm area.
(2) When it is implemented, there are many corners, which make it more difficult to design in high frequency communication field with high precision.
(3) Although it occupies very little space, its gain can be higher, and the maximum value of measurement can be +5.3dB.
3. External high-gain antenna is different from the two built-in PCB board antennas. This antenna needs to be externalized, that is, a 5-core antenna socket is installed on the node circuit board, four cores are grounded simultaneously around it, which improves the anti-interference ability. The middle pin is directly connected with the access point of 500 HM quinone impedance. It is also designed as an omnidirectional antenna with a transmission gain of 7 to 8 dB. However, it also has its own shortcomings. For example, in the case of high requirements for the shape and size of nodes, the external antenna needs to occupy a large volume in space, which may not be suitable for some occasions. At the same time, the external antenna reduces the user's receptivity in appearance, which has a certain impact on the marketization of related achievements.