Narrow-frequency band filter on circuit board for inhibiting high-frequency harmonic wave

Abstract

The invention is a narrow-bandpass filter arranged on a circuit board to suppress high-frequency harmonics. It utilizes the production technology of a printed circuit board. When making a circuit board of a wireless communication product, the metal microstrip line is used to , a microstrip line corresponding to a narrowband bandpass filter is directly manufactured on one side of the circuit board, wherein the microstrip line includes a capacitance microstrip line with a larger capacitance value, which is connected between fingers ( interdigital finger) is arranged on the circuit board to reduce the area occupied by it. Using the limited unused space on the circuit board, a narrow-band bandpass filter that can effectively suppress high-frequency harmonic noise is laid out, not only The production cost and product volume are greatly reduced, and the narrow-band technology is used to effectively suppress unwanted frequencies and only allow the required frequency bands to pass.

Description

Technical field [0001] The present invention relates to a filter for suppressing harmonic noise, in particular to the use of a printed circuit board manufacturing technology to directly lay a microstrip line on a circuit board of a wireless communication product to form a low-cost and high-performance narrow Band-pass filter, and use narrow-band technology to suppress unwanted frequencies, only pass the required frequency band, and also use harmonic suppression technology to effectively avoid unnecessary frequency interference on the receiving end of the wireless communication product. Background technique [0002] In recent years, the market demand for wireless communication products has greatly increased, making the development of wireless local area network (WLAN) faster. Especially after the IEEE 802.11 wireless local area network protocol was formulated in 1997, it not only provided a lot of wireless local area network communication. Unprecedented functions, it also provides...

AI Technical Summary

Problems solved by technology

However, when the manufacturers design and manufacture the control circuits of the wireless communication products, the filters used are generally only used to suppress the double frequency harmonics generated by the wireless communication products. High-frequency filters are not only expensive, but also relatively bulky. Therefore, for wireless communication products that are currently developing towards thin, short, cheap and high-quality designs, adding such high-frequency filters will greatly increase the production cost and volume, obviously not suitable for

[0004] In addition, when performing electromagnetic wave interference tests on wireless communication products, the harmonics generated by high-power transmission signals are often the most difficult part to pass the test, especially the double-frequency harmonics of the main frequency of the transmission signal. Harmonics with higher frequency multipliers are the most difficult to meet the standard. Therefore, how to design and produce wireless communication products that comply with relevant regulations without greatly increasing the production cost and volume of the product is an urgent problem for the design and manufacturers to overcome. an important issue to be solved

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