CN205249152U - Diplexer filter circuit - Google Patents

Abstract

The utility model relates to a diplexer filter circuit and implementation method. Filter circuit between term1 port and the term2 port is reciprocal network, can each other be inputoutput port, and radiofrequency signal RF1 from term2 port input holds through high frequency electric and follows output of term1 port or radiofrequency signal RF1 from term1 port input, holds through high frequency electric and follows the output of term2 port, filter circuit between term1 port and the term3 port is reciprocal network, can each other be inputoutput port, and radiofrequency signal RF2 from term3 port input is through high frequency inductor from output of term1 port or radiofrequency signal RF2 from term1 port input, through high frequency inductor from term3 port output. The effect is: to the high frequency electric way in shortwave and the ultrashort wave frequency range, can make the radiofrequency signal of two way different frequencies mutual isolation sharing receive and dispatch the antenna, any radiofrequency signal's all the way power is exceeded 60dB by the decay in another way radiofrequency signal's frequency range, and the isolation between two way radiofrequency signal is above 60dB.

Description

A kind of duplexer filter circuit

Technical field

The utility model circuit relates to a kind of duplexer filter circuit of mutually isolating common transmit-receive antenna for two-way radiofrequency signal.

Background technology

Under normal conditions, radio-frequency filter has two ports, and one is signal input, and another is signal output, and the impedance of two ports is all mated at 50 ohm. When needs are connected in parallel a high-pass filter and a low pass filter, form a kind of while mutually isolating the duplexer filter of common transmit-receive antenna for two-way radiofrequency signal, the common port of two parallel filters can not directly link together, and will just can link together by after suitable impedance matching. In the time that radiofrequency signal power is very large, can make duplexer filter by cavity resonator, in the time that radiofrequency signal is smaller, available discrete component is built filter circuit. Existing duplexer cavity body filter common configuration is larger, and cost is also higher simultaneously, once circuit parameter requires to change, need re-start debugging, versatility aspect Shortcomings. Also have by the duplexer of two logical LC wave filter compositions of band, shortcoming is that circuit is comparatively complicated, and design difficulty is also larger.

Summary of the invention

In view of the deficiency of prior art existence, the utility model provides a kind of duplexer filter circuit, to use discrete component to make the basic design scheme of duplexer filter, be mainly used in shortwave and ultrashort wave frequency range, radiofrequency signal RF1 frequency range is higher, radiofrequency signal RF2 frequency range is lower, and the frequency bandwidth of the two is variable, can be adjusted by the value of discrete component.

For achieving the above object, the technical scheme of taking is the utility model: a kind of duplexer filter circuit, is characterized in that: described duplexer filter circuit is by Term1 port, Term2 port, Term3 port and high frequency capacitance C1, C2, C3, C4, C5, C6, C7, C8, C9 and high-frequency inductor L1, L2, L3, L4, L5, L6, L7, L8, L9 composition, one end of described Term2 port is successively by high frequency capacitance C5, C4, C3, C2, C1, high-frequency inductor L5, L6, L7, L8, L9 connects one end of Term3 port, and the other end of described Term2 port and Term3 port is ground connection respectively, and the link of high frequency capacitance C1 and high-frequency inductor L5 is by Term1 port ground connection, high frequency capacitance C5, the link of C4 is by high-frequency inductor L4 ground connection, high frequency capacitance C4, the link of C3 is by high-frequency inductor L3 ground connection, high frequency capacitance C3, the link of C2 is by high-frequency inductor L2 ground connection, high frequency capacitance C2, the link of C1 is by high-frequency inductor L1 ground connection, high-frequency inductor L5, the link of L6 is by high frequency capacitance C6 ground connection, high-frequency inductor L6, the link of L7 is by high frequency capacitance C7 ground connection, high-frequency inductor L7, the link of L8 is by high frequency capacitance C8 ground connection, high-frequency inductor L8, the link of L9 is by high frequency capacitance C9 ground connection,

Filter circuit between Term1 port and Term2 port is reciprocal network, input/output port each other, radiofrequency signal RF1 inputs from Term2 port, input from Term1 port from the output of Term1 port or radiofrequency signal RF1 through high frequency capacitance C5, C4, C3, C2, C1 successively, export from Term2 port through high frequency capacitance C1, C2, C4, C3, C5 successively;

Filter circuit between Term1 port and Term3 port is reciprocal network, input/output port each other, radiofrequency signal RF2 inputs from Term3 port, input from Term1 port from the output of Term1 port or radiofrequency signal RF2 through high-frequency inductor L9, L8, L7, L6, L5 successively, export from Term3 port through high-frequency inductor L5, L6, L7, L8, L9 successively.

The beneficial effects of the utility model are: for the high-frequency circuit in shortwave and ultrashort wave frequency range, can make the radiofrequency signal of two-way different frequency can mutually isolate common transmit-receive antenna, the power of any road radiofrequency signal is attenuated and exceedes 60dB in the frequency range of another road radiofrequency signal, and the isolation between two-way radiofrequency signal exceedes 60dB. Circuit volume is little, and implementation method is simple, flexible, needs to increase or to reduce the exponent number of wave filter according to index, designs very convenient.

Brief description of the drawings

Fig. 1 is circuit diagram of the present utility model;

Fig. 2 is frequency response simulation curve figure.

Detailed description of the invention

As shown in Figure 1, a kind of duplexer filter circuit, is made up of Term1 port, Term2 port, Term3 port and high frequency capacitance C1, C2, C3, C4, C5, C6, C7, C8, C9 and high-frequency inductor L1, L2, L3, L4, L5, L6, L7, L8, L9.

Circuit is connected to, one end of Term2 port is successively by high frequency capacitance C5, C4, C3, C2, C1, high-frequency inductor L5, L6, L7, L8, L9 connects one end of Term3 port, the other end of Term2 port and Term3 port is ground connection respectively, the link of high frequency capacitance C1 and high-frequency inductor L5 is by Term1 port ground connection, high frequency capacitance C5, the link of C4 is by high-frequency inductor L4 ground connection, high frequency capacitance C4, the link of C3 is by high-frequency inductor L3 ground connection, high frequency capacitance C3, the link of C2 is by high-frequency inductor L2 ground connection, high frequency capacitance C2, the link of C1 is by high-frequency inductor L1 ground connection, high-frequency inductor L5, the link of L6 is by high frequency capacitance C6 ground connection, high-frequency inductor L6, the link of L7 is by high frequency capacitance C7 ground connection, high-frequency inductor L7, the link of L8 is by high frequency capacitance C8 ground connection, high-frequency inductor L8, the link of L9 is by high frequency capacitance C9 ground connection.

A kind of implementation method of duplexer filter circuit is: the filter circuit between Term1 port and Term2 port is reciprocal network, input/output port each other, radiofrequency signal RF1 inputs from Term2 port, input from Term1 port from the output of Term1 port or radiofrequency signal RF1 through high frequency capacitance C5, C4, C3, C2, C1 successively, export from Term2 port through high frequency capacitance C1, C2, C4, C3, C5 successively;

Filter circuit between Term1 port and Term3 port is reciprocal network, input/output port each other, radiofrequency signal RF2 inputs from Term3 port, input from Term1 port from the output of Term1 port or radiofrequency signal RF2 through high-frequency inductor L9, L8, L7, L6, L5 successively, export from Term3 port through high-frequency inductor L5, L6, L7, L8, L9 successively;

Filter circuit between Term1 port and Term2 port is Chebyshev's high-pass filter, the high frequency capacitance of series connection has the effect of filtering low frequency signal, high-frequency inductor in parallel also can filtering low frequency signal, by the filtering step by step of high frequency capacitance and high-frequency inductor, reach the object of filtering low frequency signal; Filter circuit between Term1 port and Term3 port is chebyshev low-pass filter, the high-frequency inductor of series connection has the effect of filtering high-frequency signal, high frequency capacitance in parallel also can filtering high-frequency signal, by the filtering step by step of high-frequency inductor and high frequency capacitance, reach the object of filtering high-frequency signal.

As shown in Figure 2, suppose that in duplexer, two-way radio frequency signal frequency is respectively 100MHz and 200MHz, filter circuit between Term1 port and Term2 port is greater than 80dB for the inhibition of 100MHz signal, approaches 0dB for the inhibition of 200MHz signal, almost can't harm.

Filter circuit between Term1 port and Term3 port is greater than 80dB for the inhibition of 200MHz signal, approaches 0dB for the inhibition of 100MHz signal, almost can't harm. So this duplexer filter structure can make two paths of signals normal work and isolation mutually respectively.

Claims (1)

1. a duplexer filter circuit, is characterized in that: described duplexer filter circuit is by Term1 port, Term2 port, Term3 port and high frequency capacitance C1, C2, C3, C4, C5, C6, C7, C8, C9 and high-frequency inductor L1, L2, L3, L4, L5, L6, L7, L8, L9 composition, one end of described Term2 port is successively by high frequency capacitance C5, C4, C3, C2, C1, high-frequency inductor L5, L6, L7, L8, L9 connects one end of Term3 port, and the other end of described Term2 port and Term3 port is ground connection respectively, and the link of high frequency capacitance C1 and high-frequency inductor L5 is by Term1 port ground connection, high frequency capacitance C5, the link of C4 is by high-frequency inductor L4 ground connection, high frequency capacitance C4, the link of C3 is by high-frequency inductor L3 ground connection, high frequency capacitance C3, the link of C2 is by high-frequency inductor L2 ground connection, high frequency capacitance C2, the link of C1 is by high-frequency inductor L1 ground connection, high-frequency inductor L5, the link of L6 is by high frequency capacitance C6 ground connection, high-frequency inductor L6, the link of L7 is by high frequency capacitance C7 ground connection, high-frequency inductor L7, the link of L8 is by high frequency capacitance C8 ground connection, high-frequency inductor L8, the link of L9 is by high frequency capacitance C9 ground connection,

Filter circuit between Term1 port and Term2 port is reciprocal network, input/output port each other, radiofrequency signal RF1 inputs from Term2 port, input from Term1 port from the output of Term1 port or radiofrequency signal RF1 through high frequency capacitance C5, C4, C3, C2, C1 successively, export from Term2 port through high frequency capacitance C1, C2, C4, C3, C5 successively;

Filter circuit between Term1 port and Term3 port is reciprocal network, input/output port each other, radiofrequency signal RF2 inputs from Term3 port, input from Term1 port from the output of Term1 port or radiofrequency signal RF2 through high-frequency inductor L9, L8, L7, L6, L5 successively, export from Term3 port through high-frequency inductor L5, L6, L7, L8, L9 successively.