CN100530957C - Two-channel band pass filter - Google Patents

Abstract

Being setup on base plate, the dual channel band-pass filter includes input end, output end, first resonator, and second resonator. The input end is in use for feeding in electromagnetic wave signal; and the output end is in use for feeding out electromagnetic wave signal. The input end and the output end are setup in parallel. Being formed on central portion of the first resonator approximately, first groove is connected to the input end electrically. Being formed on central portion approximately of the second resonator side by side to the first resonator, second groove is connected to the output end electrically. Being workable at adjacent closed two frequency bands, the dual channel band-pass filter possesses good filtering effect.

Description

Dual Channel Bandpass Filter

【Technical field】

The invention relates to a high-frequency component, in particular to a filter.

【Background technique】

In recent years, due to the great increase in the market demand for mobile communication products, the development of wireless communication has become more rapid. Among the many wireless communication standards, the most eye-catching one is the 802.11 wireless communication standard formulated by the Institute of Electrical and Electronics Engineers (hereinafter referred to as: IEEE). LAN (Wireless Local Area Network) protocol. Established in 1997, the agreement not only provides many unprecedented functions in wireless communication, but also provides solutions that enable various brands of wireless communication products to communicate with each other. The establishment of the agreement undoubtedly opened a new milestone for the development of wireless communication.

The mobile phone with WiFi (Wireless Fidelity) function has a faster signal transmission speed than the traditional mobile network. The signal transmission speed of the existing GSM (Global System for Mobile Communications) mobile phone is up to 9.6Kbps, while the mobile phone with WiFi function Its signal transmission speed can reach up to 54Mbps (IEEE 802.11g). In addition, because WiFi uses the channel of the Internet, the cost is relatively low.

Existing phone manufacturers embed the WiFi function into GSM mobile phones (dual-mode mobile phones), so as to realize the purpose of talking on both the GSM (working frequency band of 1900MHz) network and the wireless local area network (working frequency band of 2.4GHz). Since 1900MHz and 2.4GHz are two frequency bands that are very close to each other, when a dual-mode mobile phone intends to use the above two communication protocols at the same time, it is required that the filter of the above-mentioned dual-mode mobile phone can work in two frequency bands that are very close to each other. However, existing filters cannot meet this requirement, resulting in poor filtering performance for dual-mode handsets.

【Content of invention】

In order to solve the above-mentioned deficiencies in the prior art, it is necessary to provide a dual-channel bandpass filter that can work in two frequency bands that are very close to each other.

A dual-channel band-pass filter is arranged on a substrate. The dual-channel band-pass filter includes an input end, an output end, a first resonator, and a second resonator. The input end is used to feed in electromagnetic wave signals, and the output end is used to feed out electromagnetic wave signals, and is arranged in parallel with the input end. The first resonator is electrically connected to the input end, including a first outer band, a first inner band that is arranged in parallel with the first outer band and has the same length, a first connecting portion, and a length equal to that of the first connecting portion and The first inner band includes a first protruding part disposed in the middle of the first inner band and facing the first outer band. The first outer band and the first inner band are vertically connected with the first connecting portion and the second connecting portion and form a first groove at the center of the first resonator. The second resonator is electrically connected to the output end, including a second outer band, a second inner band arranged in parallel with the second outer band and having the same length, a third connection portion, and a length and length of the third connection portion. The second inner band has a fourth connecting portion with the same width and is parallel to each other. The second inner band includes a second protruding portion disposed in the middle of the second inner band and facing the second outer band. The second outer strip and the second inner strip are vertically connected with the third connecting portion and the fourth connecting portion and form a second groove at the center of the second resonator.

The dual-channel bandpass filter in the embodiment of the present invention can work in two adjacent frequency bands due to the groove design and side-by-side arrangement of the resonators.

【Description of drawings】

FIG. 1 is a schematic diagram of a dual-channel bandpass filter in an embodiment of the present invention.

FIG. 2 is a schematic diagram of the application of a dual-channel bandpass filter in an embodiment of the present invention.

FIG. 3 is a test diagram of a dual-channel bandpass filter in an embodiment of the present invention obtained through electromagnetic simulation.

【Detailed ways】

Please refer to FIG. 1 , which is a schematic diagram of a dual-channel bandpass filter 10 in an embodiment of the present invention.

In this embodiment, the dual-channel bandpass filter 10 is disposed on the substrate 20 , and the dual-channel bandpass filter 10 includes an input terminal 100 , an output terminal 120 , a first resonator 140 , and a second resonator 160 .

The input end 100 is used to feed in electromagnetic wave signals, and the output end 120 is used to feed out electromagnetic wave signals. The input terminal 100 is arranged in parallel with the output terminal 120 and is electrically connected to the first resonator 140 . The second resonator 160 is arranged symmetrically with the first resonator 140 and is electrically connected to the output terminal 120 . The shape of the first resonator 140 is substantially the same as that of the second resonator 160 .

The first resonator 140 includes a first outer strip 141 , a first inner strip 142 , a first connection part 143 , and a second connection part 144 . A first protruding portion 145 is disposed in the middle of the first inner band 142 . The first outer belt 141 and the first inner belt 142 are arranged in parallel and have the same length. The length and width of the first connecting portion 143 and the second connecting portion 144 are equal and parallel to each other. The first outer band 141 , the first inner band 142 , the first connecting portion 143 and the second connecting portion 144 are vertically connected end to end to form a first groove 146 .

The second resonator 160 includes a second outer strip 161 , a second inner strip 162 , a third connection part 163 , and a fourth connection part 164 . The middle of the second inner band 162 is provided with a second protrusion 165 . The second outer belt 161 and the second inner belt 162 are arranged in parallel and have the same length. The length and width of the third connecting portion 163 and the fourth connecting portion 164 are equal and parallel to each other. The second outer band 161 , the second inner band 162 , the third connecting portion 163 and the fourth connecting portion 164 are vertically connected end to end to form a second groove 166 .

The third connecting portion 163 is located on the same straight line as the first connecting portion 143 , and the fourth connecting portion 164 is located on the same straight line as the second connecting portion 144 . The first inner band 142 is disposed adjacent to the second inner band 162 . The first protrusion 145 faces the first outer band 141 , and the second protrusion 165 faces the second outer band 161 .

Please refer to FIG. 2 , which is a schematic diagram showing the application of the dual-channel bandpass filter 10 in the embodiment of the present invention.

In order to make the dual-channel bandpass filter 10 work normally in the embodiment of the present invention, the input end 100 of the dual-channel bandpass filter 10 is electrically connected to the first converter 300, and the output end 120 is electrically connected to the second converter. 400. The first converter 300 includes a first conversion part 302 and a second conversion part 304 . The second converter 400 includes a third converting unit 402 and a fourth converting unit 404 . One end of the first conversion unit 302 is electrically connected to the input terminal 100 , and the other end is electrically connected to the second conversion unit 304 . One end of the second conversion part 304 is electrically connected to the first conversion part 302 , and the other end is electrically connected to a radio frequency module (not shown). One end of the third conversion unit 402 is electrically connected to the output terminal 120 , and the other end is electrically connected to the fourth conversion unit 404 . One end of the fourth converting portion 404 is electrically connected to the third converting portion 402 , and the other end is electrically connected to an antenna (not shown).

In this embodiment, in order to make the dual-channel bandpass filter 10 work in two frequency bands whose center frequencies are 1900MHz and 2.4GHz, the resistance values of the first conversion part 302 and the third conversion part 402 are 95 ohms, and the resistance of the second conversion part 302 is 95 ohms. The resistance of the conversion part 304 and the fourth conversion part 404 is 68 ohms.

Please refer to FIG. 3 , which shows a test diagram obtained by electromagnetic simulation after the dual-channel bandpass filter 10 is connected to the first converter 300 and the second converter 400 in the embodiment of the present invention.

In the figure, the horizontal axis represents the frequency (unit: GHz) of the signal passing through the dual-channel bandpass filter 10 in the embodiment of the present invention, and the vertical axis represents the amplitude (unit: dB), including the scattering parameter (S-parameter: S21) of transmission and the magnitude of the reflected scattering parameter (S-parameter: S11). The scattering parameter dB[(S2, 1)] of transmission represents the relationship between the input power of the signal and the output power of the signal through the dual-channel bandpass filter 10 in the embodiment of the present invention, and its corresponding mathematical function is: dB[ (S2, 1)]=20*Log|S21|. During the signal transmission process of the dual-channel bandpass filter 10 in the embodiment of the present invention, part of the power of the signal is reflected back to the signal source. The power that is reflected back to the signal source is called reflected power. By the relationship between the input power of the signal of the dual-channel bandpass filter 10 and the reflected power of the signal in the embodiment of the present invention, its corresponding mathematical function is: dB[(S1, 1)]=20*Log|S11| .

It can be seen from FIG. 3 that in the embodiment of the present invention, the dual-channel bandpass filter 10 cooperates with the first converter 300 and the second converter 400 to not only work in two adjacent frequency bands (dual channels), but also has a good dual-channel filtering effect . It can be seen from the curve dB[(S2, 1)] that a steep "transition slope" is formed between the passband frequency band and the attenuation frequency band, and the insertion loss of the signal within the passband frequency range is close to zero. At the same time, it can be observed from the curve dB[(S1, 1)] that the absolute value of the signal reflection loss within the passband frequency range is greater than 10, while outside the passband frequency band, the absolute value of the signal reflection loss is less than 10. This shows that the dual-channel bandpass filter 10 has a good filtering effect when working in two frequency bands that are very close to each other.

In the embodiment of the present invention, the working frequency band of the dual-channel bandpass filter 10 is not limited to 1900MHz and 2.4GHz. Those skilled in the art can change the first outer band 141, the first inner band 142, The length and width of the first connecting portion 143, the second connecting portion 144, and the second outer band 161, the second inner band 162, the third connecting portion 163, and the fourth connecting portion 164 of the second resonator 160 can reach The purpose of changing the operating frequency band of the dual-channel bandpass filter 10 .

Claims (5)

1. a dual-channel bandpass filter is arranged on the substrate, and is characterized in that said dual-channel bandpass filter comprises: The input terminal is used to feed in electromagnetic wave signals; The first resonator, electrically connected to the input end, includes a first outer band, a first inner band arranged in parallel with the first outer band and having the same length, a first connecting portion, and a first connecting portion The length and width of the second connecting portion are equal and parallel to each other. The first inner band includes a first protruding portion disposed in the middle of the first inner band and facing the first outer band. The first outer band The strip and the first inner strip are vertically connected to the first connection part and the second connection part and form a first groove at the center of the first resonator; The second resonator, arranged side by side with the first resonator, includes a second outer band, a second inner band arranged in parallel with the second outer band and having the same length, a third connecting portion, and a second inner band with the same length as the third connecting portion. The length and width of the connecting portion are equal to the fourth connecting portion parallel to each other. The second inner belt includes a second protruding portion disposed in the middle of the second inner belt and facing the second outer belt. The second outer belt And the second inner band is vertically connected with the third connection part and the fourth connection part and forms a second groove at the center of the second resonator; and The output end is used to feed out the electromagnetic wave signal, the output end is arranged in parallel with the input end, and is electrically connected to the second resonator. 2. The dual-channel bandpass filter according to claim 1, wherein the first resonator and the second resonator are arranged symmetrically. 3. The dual-channel bandpass filter according to claim 1, wherein the shape of the first resonator is the same as that of the second resonator. 4. The dual-channel bandpass filter according to claim 1, wherein the third connecting portion is located on the same straight line as the first connecting portion, and the fourth connecting portion is located on the same straight line as the second connecting portion . 5. The dual-channel bandpass filter of claim 1, wherein the first inner band is adjacent to the second inner band.

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