CN104064847B - The tunable micro-band of a kind of degree of coupling is across directional coupler - Google Patents

Abstract

The invention discloses the tunable micro-band of a kind of degree of coupling across directional coupler, comprise medium substrate; Described medium substrate is provided with Coupled Miccrostrip Lines, flying capcitor, the first degree of coupling tuning circuit and the second degree of coupling tuning circuit, first power supply circuits of powering to the first degree of coupling tuning circuit, second power supply circuits of powering to the second degree of coupling tuning circuit and 4 the I/O microstrip lines be connected with described Coupled Miccrostrip Lines two ends; Described first degree of coupling tuning circuit is all connected described first microstrip line with the first power supply circuits; Described second degree of coupling tuning circuit is all connected described second microstrip line with the second power supply circuits; Described first degree of coupling tuning circuit comprises the tuning branch road of at least one degree of coupling, and the tuning branch road of this degree of coupling comprises switching diode, tuning coil, biasing resistor and capacitance I; The present invention can complete the degree of coupling and change with the inductance value difference of tuning coil, realizes the degree of coupling tunable.

Description

The tunable micro-band of a kind of degree of coupling is across directional coupler

Technical field

The invention belongs to electronic technology field, relate to a kind of microwave device, be specially the tunable micro-band of a kind of degree of coupling across directional coupler.

Background technology

Directional coupler is four port microwave devices input signal power being divided into two output signals in specific frequency range according to special ratios, and its major function has signal power distribution/synthesis, power samples/detects and the feed etc. of antenna array.Along with the development of mobile communication technology, directional coupler has been widely applied in the microwave circuits such as frequency mixer, filter, balanced power amplifiers, phase shifter and antenna array system.

According to the position of isolated port relative to input port, directional coupler can be divided in the same way, oppositely with across three kinds of forms.Particularly, if input is held on same transmission line with straight-through, coupled end and isolation end are on another transmission lines, and input and isolation end are in the same side, then form coupler in the same way; If input is held on same transmission line with straight-through, coupled end and isolation end are on another transmission lines, and input and coupled end are in the same side, then form reverse coupler; If input and isolation end are on same transmission line, coupled end is held on another transmission lines with straight-through, and input and isolation end are in the same side, then form across directional coupler.

Wherein, the planar circuit directional coupler be made up of microstrip line is a kind of way of realization of directional coupler, it is realized by the printed circuit board technology of maturation, have volume little, be easy to the feature such as integrated, compared to the directional coupler of other structure, more easily be connected with microwave solid-state device, be widely used in the transmission such as military channels, radar system and mobile communication microwave system, test and location association area, and in the system such as in-door covering, WLAN and MPS process.Simultaneously, what be made up of microstrip line has the little feature of low cost, easily processing and volume across directional coupler, and because its coupled end and straight-through end are on a transmission lines, therefore when micro-band is applied to microwave circuit across directional coupler, can circuit cross-overs be avoided, and simplify circuit layout, therefore, along with the extensive research and apply of Butler matrix and balance amplifier, micro-band receives concern across the research of directional coupler.In addition, in recent years, along with the increase of modern mobile radio standard, need front end microwave device reducing costs and to reduce on the basis of whole circuit volume, adapt to the environment of constantly change, and there is reconfigurability.

Summary of the invention

The present invention is directed to the proposition of above problem, and develop the tunable micro-band of a kind of degree of coupling across directional coupler.

Technological means of the present invention is as follows:

The tunable micro-band of a kind of degree of coupling, across directional coupler, comprises medium substrate; Described medium substrate is provided with Coupled Miccrostrip Lines, flying capcitor, the first degree of coupling tuning circuit and the second degree of coupling tuning circuit, first power supply circuits of powering to the first degree of coupling tuning circuit, second power supply circuits of powering to the second degree of coupling tuning circuit and 4 the I/O microstrip lines be connected with described Coupled Miccrostrip Lines two ends;

Described Coupled Miccrostrip Lines comprises the first microstrip line and the second microstrip line that are parallel to each other; Described flying capcitor is placed between described first microstrip line and described second microstrip line; Described first degree of coupling tuning circuit is all connected described first microstrip line with the first power supply circuits; Described second degree of coupling tuning circuit is all connected described second microstrip line with the second power supply circuits; Described first power supply circuits comprise direct voltage source and choke induction; Described first degree of coupling tuning circuit comprises the tuning branch road of at least one degree of coupling, and the tuning branch road of this degree of coupling comprises switching diode, tuning coil, biasing resistor and capacitance I; Described switching diode negative electrode connects described biasing resistor one end and described capacitance I one end by tuning coil; The described biasing resistor other end can be connected with described direct voltage source negative pole; Described capacitance I other end ground connection; Described choke induction one end connects described direct voltage source positive pole, and the other end connects described switching diode anode, and described choke induction is connected described first microstrip line with the phase contact of described switching diode by capacitance II; Described second power supply circuits are identical with described first power supply circuit construction; Described second degree of coupling tuning circuit is identical with described first degree of coupling tuning circuit structure;

Further, the tuning branch road of the described degree of coupling also comprises shunt capacitance, and this shunt capacitance one end is connected with described direct voltage source negative pole, other end ground connection;

Further, described flying capcitor has 3, is placed in two ends and the middle part of described Coupled Miccrostrip Lines respectively;

Further, when the first degree of coupling tuning circuit and the second degree of coupling tuning circuit include the tuning branch road of degree of coupling, regulate described micro-band across the degree of coupling of directional coupler by changing described tuning coil;

Further, when the first degree of coupling tuning circuit and the second degree of coupling tuning circuit include the tuning branch road of the two or more degree of coupling, the inductance value of the tuning coil included by the tuning branch road of each degree of coupling is different, regulates described micro-band across the degree of coupling of directional coupler by changing with the tuning branch road of the degree of coupling that the first power supply circuits are connected with the second power supply circuits;

Further, according to formula $k=\left|\frac{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}-Z_0^2}{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}\tan \left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}+Z_0^2+{\mathrm{jZ}}_0{Z}_{ce}\frac{2Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)-{\mathrm{\ωLtan}}^2\left(\frac{\mathrm{\θ}}{2}\right)+\mathrm{\ω}L}{Z_{ce}-\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)}}\right|,$ Realize the adjustment of described micro-band across the degree of coupling of directional coupler;

Wherein, k is the degree of coupling, the Z of described micro-band across directional coupler _cefor the even mode impedance value of described Coupled Miccrostrip Lines, θ be the electrical length of described Coupled Miccrostrip Lines, ω=2 π f, f be for described micro-band is across inductance value, the Z of the centre frequency of directional coupler, the tuning coil of L included by the tuning branch road of the degree of coupling that is connected with the first power supply circuits or the second power supply circuits ₀it is 50 ohm.

Owing to have employed technique scheme, a kind of degree of coupling provided by the invention is tunable micro-band is across directional coupler, the degree of coupling can be completed change with the inductance value difference of tuning coil, realize the degree of coupling tunable, have that structure is simple, the feature of low cost, easily process and reconfigurability simultaneously, be suitable for extensive popularization.

Accompanying drawing explanation

Fig. 1 is the structural representation of micro-band of the present invention across directional coupler;

Fig. 2 is micro-band of the present invention across the directional coupler degree of coupling with the different test curve figure of the inductance value of tuning coil;

Fig. 3 is micro-band of the present invention across directional coupler return loss with the different test curve figure of the inductance value of tuning coil;

Fig. 4 is micro-band of the present invention across directional coupler isolation with the different test curve figure of the inductance value of tuning coil;

Fig. 5 is micro-band of the present invention across directional coupler output port phase difference with the different test curve figure of the inductance value of tuning coil.

In figure: 1, medium substrate, 2, Coupled Miccrostrip Lines, the 3, first degree of coupling tuning circuit, the 4, second degree of coupling tuning circuit, 5, the first power supply circuits, the 6, second power supply circuits, 7, I/O microstrip line, 8, the first microstrip line, the 9, second microstrip line, 10, the tuning branch road of the degree of coupling.

Embodiment

A kind of degree of coupling is as shown in Figure 1 tunable micro-band, across directional coupler, comprises medium substrate 1; Described medium substrate 1 is provided with Coupled Miccrostrip Lines 2, flying capcitor, the first degree of coupling tuning circuit 3 and the second degree of coupling tuning circuit 4, first power supply circuits 5 of powering to the first degree of coupling tuning circuit 3, second power supply circuits 6 of powering to the second degree of coupling tuning circuit 4 and 4 the I/O microstrip lines 7 be connected with described Coupled Miccrostrip Lines 2 two ends; Described Coupled Miccrostrip Lines 2 comprises the first microstrip line 8 and the second microstrip line 9 be parallel to each other; Described flying capcitor is placed between described first microstrip line 8 and described second microstrip line 9; Described first degree of coupling tuning circuit 3 and the first power supply circuits 5 are all connected described first microstrip line 8; Described second degree of coupling tuning circuit 4 and the second power supply circuits 6 are all connected described second microstrip line 9; Described first power supply circuits 5 comprise direct voltage source and choke induction; Described first degree of coupling tuning circuit 3 comprises the tuning branch road 10 of at least one degree of coupling, and the tuning branch road 10 of this degree of coupling comprises switching diode, tuning coil, biasing resistor and capacitance I; Described switching diode negative electrode connects described biasing resistor one end and described capacitance I one end by tuning coil; The described biasing resistor other end can be connected with described direct voltage source negative pole; Described capacitance I other end ground connection; Described choke induction one end connects described direct voltage source positive pole, and the other end connects described switching diode anode, and described choke induction is connected described first microstrip line 8 with the phase contact of described switching diode by capacitance II; Described second power supply circuits 6 are identical with described first power supply circuits 5 structure; Described second degree of coupling tuning circuit 4 is identical with described first degree of coupling tuning circuit 3 structure; Further, the tuning branch road 10 of the described degree of coupling also comprises shunt capacitance, and this shunt capacitance one end is connected with described direct voltage source negative pole, other end ground connection; Further, described flying capcitor has 3, is placed in two ends and the middle part of described Coupled Miccrostrip Lines 2 respectively; Further, when the first degree of coupling tuning circuit 3 and the second degree of coupling tuning circuit 4 include the tuning branch road 10 of degree of coupling, regulate described micro-band across the degree of coupling of directional coupler by changing described tuning coil; Further, when the first degree of coupling tuning circuit 3 and the second degree of coupling tuning circuit 4 include the tuning branch road 10 of the two or more degree of coupling, the inductance value of the tuning coil included by the tuning branch road 10 of each degree of coupling is different, regulates described micro-band across the degree of coupling of directional coupler by changing with the tuning branch road of the degree of coupling 10 that the first power supply circuits 5 are connected with the second power supply circuits 6; Further, according to formula $k=\left|\frac{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}-Z_0^2}{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}\tan \left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}+Z_0^2+{\mathrm{jZ}}_0{Z}_{ce}\frac{2Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)-{\mathrm{\ωLtan}}^2\left(\frac{\mathrm{\θ}}{2}\right)+\mathrm{\ω}L}{Z_{ce}-\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)}}\right|,$ Realize the adjustment of described micro-band across the degree of coupling of directional coupler; Wherein, k is the degree of coupling, the Z of described micro-band across directional coupler _cefor the even mode impedance value of described Coupled Miccrostrip Lines 2, θ be the electrical length of described Coupled Miccrostrip Lines 2, ω=2 π f, f be for described micro-band is across inductance value, the Z of the centre frequency of directional coupler, the tuning coil of L included by the tuning branch road 10 of the degree of coupling that is connected with the first power supply circuits 5 or the second power supply circuits 6 ₀it is 50 ohm.

Medium substrate of the present invention is used for supports parallel coupled microstrip line, flying capcitor, the first degree of coupling tuning circuit, the second degree of coupling tuning circuit, the first power supply circuits, the second power supply circuits and I/O microstrip line; Described I/O microstrip line is 50 ohm, and 4 described I/O microstrip lines can be measure-alike; Described first degree of coupling tuning circuit is all connected described first microstrip line by capacitance II with the first power supply circuits, particularly, can connect the centre position of described first microstrip line; Similarly, described second degree of coupling tuning circuit is all connected described second microstrip line by capacitance III with the second power supply circuits, particularly, can connect the centre position of described second microstrip line; Described choke induction one end connects described direct voltage source positive pole, the other end connects described switching diode anode, described choke induction is connected described first microstrip line with the phase contact of described switching diode by capacitance II, by the setting of choke induction, can control AC signal; The choke induction that described first degree of coupling tuning circuit comprises is connected described first microstrip line with the phase contact of described switching diode by the electric capacity C4 shown in capacitance II Fig. 1; The choke induction that described second degree of coupling tuning circuit comprises is connected described second microstrip line with the phase contact of described switching diode by the electric capacity C15 shown in capacitance III Fig. 1, and electric capacity C4 and electric capacity C15 can ensure that the input/output port of coupler can not be mixed into direct current signal; Described flying capcitor has 3, and wherein electric capacity C1, electric capacity C2 and electric capacity C3 are flying capcitor, and capacitance is equal.

First degree of coupling tuning circuit of the present invention and the second degree of coupling tuning circuit comprise the tuning branch road of at least one degree of coupling respectively, have illustrated that the first degree of coupling tuning circuit and the second degree of coupling tuning circuit include 5 tuning branch roads of the degree of coupling respectively in Fig. 1, second degree of coupling tuning circuit is identical with the first degree of coupling tuning circuit structure, namely the degree of coupling tuning circuit that the first microstrip line and the second microstrip line are connected respectively has consistent structure, and the tuning branch road of the described degree of coupling comprises switching diode, tuning coil, biasing resistor and capacitance I, 5 the tuning branch roads of the degree of coupling set included by the first degree of coupling tuning circuit are respectively the tuning branch road of the degree of coupling I, the tuning branch road of the degree of coupling II, the tuning branch road of the degree of coupling III, the tuning branch road of the degree of coupling IV and the tuning branch road V of the degree of coupling, as shown in Figure 1, the tuning branch road I of the degree of coupling comprises switching diode D1, tuning coil L2, biasing resistor R1 and capacitance I C5, the tuning branch road II of the degree of coupling comprises switching diode D2, tuning coil L3, biasing resistor R2 and capacitance I C7, the tuning branch road III of the degree of coupling comprises switching diode D3, tuning coil L4, biasing resistor R3 and capacitance I C9, the tuning branch road IV of the degree of coupling comprises switching diode D4, tuning coil L5, biasing resistor R4 and capacitance I C12, the tuning branch road V of the degree of coupling comprises switching diode D5, tuning coil L6, biasing resistor R5 and capacitance I C14, first power supply circuits are identical with the second power supply circuit construction, and as shown in Figure 1, the first power supply circuits comprise direct voltage source DC1 and choke induction L1, and the second power supply circuits comprise direct voltage source DC2 and choke induction L7, when the first degree of coupling tuning circuit and the second degree of coupling tuning circuit include the tuning branch road of degree of coupling, by changing described tuning coil to regulate described micro-band across the degree of coupling of directional coupler during practical application, when the tuning coil of replacing first degree of coupling tuning circuit, the tuning coil of synchronous replacing second degree of coupling tuning circuit, the inductance value of the tuning coil of the first degree of coupling tuning circuit after replacing is identical with the inductance value of the tuning coil of the second degree of coupling tuning circuit after replacing, to ensure that the degree of coupling tuning circuit that the first microstrip line and the second microstrip line are connected respectively has consistent structure, when the first degree of coupling tuning circuit and the second degree of coupling tuning circuit include the tuning branch road of the two or more degree of coupling, the first degree of coupling tuning circuit is shown and the second degree of coupling tuning circuit includes 5 tuning branch roads of the degree of coupling respectively as Fig. 1, the inductance value arranging the tuning coil included by the tuning branch road of each degree of coupling during practical application is different, further, regulate described micro-band across the degree of coupling of directional coupler by changing with the tuning branch road of the degree of coupling that the first power supply circuits are connected with the second power supply circuits, be specially tuning for above-mentioned degree of coupling branch road I, the tuning branch road II of the degree of coupling, the tuning branch road III of the degree of coupling, the tuning branch road of the degree of coupling IV or the tuning branch road V of the degree of coupling are connected with the first power supply circuits, because the described biasing resistor other end can be connected with described direct voltage source negative pole, specifically by connecting or disconnecting the biasing resistor other end and described direct voltage source negative pole, and then realize the tuning branch road I of the degree of coupling, the tuning branch road II of the degree of coupling, the tuning branch road III of the degree of coupling, the tuning branch road of the degree of coupling IV or the tuning branch road V of the degree of coupling are connected with the first power supply circuits or disconnect, similarly, the tuning branch road of the degree of coupling included by second degree of coupling tuning circuit is also by identical mode, due to, second degree of coupling tuning circuit is identical with the first degree of coupling tuning circuit structure, namely the tuning branch road of the degree of coupling effectively connected in the second degree of coupling tuning circuit, identical with the inductance value of the tuning coil included by the tuning branch road of the degree of coupling that the first degree of coupling tuning circuit effectively connects.Further, the described biasing resistor other end can be connected weld tabs or via hole respectively with direct voltage source negative pole, by whether being provided with connecting line between two weld tabs or via hole, realize connection or the disconnection of the described biasing resistor other end and direct voltage source negative pole, when the described biasing resistor other end is connected via hole respectively with direct voltage source negative pole, described connecting line is placed in the back side of described medium substrate, in schematic diagram shown in Fig. 1, the first degree of coupling tuning circuit and the second degree of coupling tuning circuit include 5 tuning branch roads of the degree of coupling respectively, the tuning branch road I of the setting degree of coupling, the tuning branch road II of the degree of coupling, the tuning branch road III of the degree of coupling, when the tuning branch road of the degree of coupling IV or the tuning branch road V of the degree of coupling are connected with the first power supply circuits respectively, the inductance value of corresponding tuning coil is 1nH, 2nH, 4nH, 10nH, and 22nH, second power supply circuits connect the tuning branch road of the degree of coupling adopting same structure, in addition, when the first power supply circuits and the second power supply circuits do not take over the tuning branch road of what degree of coupling, the inductance value of corresponding tuning coil is ∞ nH, Fig. 2 shows micro-band of the present invention across the directional coupler degree of coupling with the different test curve figure of the inductance value of tuning coil, the described different degree of coupling realizes by arranging the tuning branch road of the degree of coupling with the tuning coil of different induction value, first degree of coupling tuning circuit, second degree of coupling tuning circuit adopts consistent structure, and then the micro-band obtaining 6 kinds of degrees of coupling is across directional coupler, the centre frequency of coupler gets 1.6GHz, 6 kinds of degrees of coupling are respectively 0.7dB, 1.2dB, 1.9dB, 3.0dB, 4.0dB and 5.1dB, Fig. 3 is micro-band of the present invention across directional coupler return loss with the different test curve figure of the inductance value of tuning coil, Fig. 4 is micro-band of the present invention across directional coupler isolation with the different test curve figure of the inductance value of tuning coil, Fig. 5 is micro-band of the present invention across directional coupler output port phase difference with the different test curve figure of the inductance value of tuning coil, different tuning coils may correspond to the tuning branch road of the above-mentioned different degree of coupling, when the first degree of coupling tuning circuit and the second degree of coupling tuning circuit include the tuning branch road of degree of coupling, also by changing described tuning coil to realize.

Micro-band of the present invention is as follows across the technical indicator of directional coupler:

Centre frequency: 1.6GHz

The attainable degree of coupling is not limited to this: 0.5dB, 1.0dB, 2.0dB, 3.0dB, 4.0dB, 5.0dB;

Isolation: >=15dB

Return loss: >=15dB

Output port phase difference: 90 ± 5 °.

A kind of degree of coupling provided by the invention is tunable micro-band is across directional coupler, the degree of coupling can be completed change with the inductance value difference of tuning coil, realize the degree of coupling tunable, have that structure is simple, the feature of low cost, easily process and reconfigurability simultaneously, be suitable for extensive popularization; Described micro-band is across the degree of coupling of directional coupler by the control of degree of coupling tuning circuit, and do not need to redesign circuit, the inductance value by means of only change tuning coil can reach the object realizing the degree of coupling and regulate.

Micro-band of the present invention across directional coupler, according to formula $k=\left|\frac{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}-Z_0^2}{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}\tan \left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}+Z_0^2+{\mathrm{jZ}}_0{Z}_{ce}\frac{2Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)-{\mathrm{\ωLtan}}^2\left(\frac{\mathrm{\θ}}{2}\right)+\mathrm{\ω}L}{Z_{ce}-\mathrm{\ω}Ltan\left(\frac{\mathrm{\θ}}{2}\right)}}\right|,$ Realize the adjustment of described micro-band across the degree of coupling of directional coupler;

Wherein, k is the degree of coupling, the Z of described micro-band across directional coupler _cefor the even mode impedance value of described Coupled Miccrostrip Lines, θ be the electrical length of described Coupled Miccrostrip Lines, inductance value, the Z of ω=2 π f, f to be described micro-band across the centre frequency of directional coupler, L the be tuning coil comprised with the tuning branch road of the degree of coupling of the first power supply circuits and the second power supply circuits ₀be 50 ohm, j be plural number imaginary part, Z _ce, θ, f, L be known parameters, artificially set by designing requirement or choose.

In addition before designing antenna, by formula calculate the odd mode impedance value Z of Coupled Miccrostrip Lines _co, and pass through formula calculate the capacitance C of flying capcitor, the electrical length of described first microstrip line and the second microstrip line can be set to described micro-band across directional coupler centre frequency corresponding to wavelength 1/4, draw the electrical length θ of Coupled Miccrostrip Lines further.

The above; be only the present invention's preferably embodiment; but protection scope of the present invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses; be equal to according to technical scheme of the present invention and inventive concept thereof and replace or change, all should be encompassed within protection scope of the present invention.

Claims (6)

1. the tunable micro-band of the degree of coupling is across a directional coupler, it is characterized in that comprising medium substrate (1); Described medium substrate (1) is provided with Coupled Miccrostrip Lines (2), flying capcitor, the first degree of coupling tuning circuit (3) and the second degree of coupling tuning circuit (4), first power supply circuits (5) of powering to the first degree of coupling tuning circuit (3), second power supply circuits (6) of powering to the second degree of coupling tuning circuit (4) and 4 the I/O microstrip lines (7) be connected with described Coupled Miccrostrip Lines (2) two ends;

Described Coupled Miccrostrip Lines (2) comprises the first microstrip line (8) and the second microstrip line (9) that are parallel to each other; Described flying capcitor is placed between described first microstrip line (8) and described second microstrip line (9); Described first degree of coupling tuning circuit (3) is all connected described first microstrip line (8) with the first power supply circuits (5); Described second degree of coupling tuning circuit (4) is all connected described second microstrip line (9) with the second power supply circuits (6); Described first power supply circuits (5) comprise direct voltage source and choke induction; Described first degree of coupling tuning circuit (3) comprises the tuning branch road of at least one degree of coupling (10), and the tuning branch road of this degree of coupling (10) comprises switching diode, tuning coil, biasing resistor and capacitance I; Described switching diode negative electrode connects described biasing resistor one end and described capacitance I one end by tuning coil; The described biasing resistor other end can be connected with described direct voltage source negative pole; Described capacitance I other end ground connection; Described choke induction one end connects described direct voltage source positive pole, and the other end connects described switching diode anode, and described choke induction is connected described first microstrip line (8) with the phase contact of described switching diode by capacitance II; Described second power supply circuits (6) are identical with described first power supply circuits (5) structure; Described second degree of coupling tuning circuit (4) is identical with described first degree of coupling tuning circuit (3) structure.

2. the tunable micro-band of a kind of degree of coupling according to claim 1 is across directional coupler, it is characterized in that the tuning branch road of the described degree of coupling (10) also comprises shunt capacitance, this shunt capacitance one end is connected with described direct voltage source negative pole, other end ground connection.

3. the tunable micro-band of a kind of degree of coupling according to claim 1 is across directional coupler, it is characterized in that described flying capcitor has 3, is placed in two ends and the middle part of described Coupled Miccrostrip Lines (2) respectively.

4. the tunable micro-band of a kind of degree of coupling according to claim 1 is across directional coupler, it is characterized in that, when the first degree of coupling tuning circuit (3) and the second degree of coupling tuning circuit (4) include a tuning branch road of the degree of coupling (10), regulating described micro-band across the degree of coupling of directional coupler by changing described tuning coil.

5. the tunable micro-band of a kind of degree of coupling according to claim 1 is across directional coupler, it is characterized in that when the first degree of coupling tuning circuit (3) and the second degree of coupling tuning circuit (4) include the tuning branch road of the two or more degree of coupling (10), the inductance value of the tuning coil included by the tuning branch road of each degree of coupling (10) is different, regulates described micro-band across the degree of coupling of directional coupler by changing with the tuning branch road of the degree of coupling (10) that the first power supply circuits (5) are connected with the second power supply circuits (6).

6. a kind of degree of coupling according to claim 4 or 5 is tunable micro-band, across directional coupler, is characterized in that according to formula $k=\left|\frac{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}L\tan \left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}-Z_0^2}{Z_{ce}^{2}tan\left(\frac{\mathrm{\θ}}{2}\right)\frac{\mathrm{\ω}L+Z_{ce}\tan \left(\frac{\mathrm{\θ}}{2}\right)}{\mathrm{\ω}L\tan \left(\frac{\mathrm{\θ}}{2}\right)-Z_{ce}}+Z_0^2+{\mathrm{jZ}}_0{Z}_{ce}\frac{2Z_{ce}tan\left(\frac{\mathrm{\θ}}{2}\right)-\mathrm{\ω}L{\tan }^2\left(\frac{\mathrm{\θ}}{2}\right)+\mathrm{\ω}L}{Z_{ce}-\mathrm{\ω}L\tan \left(\frac{\mathrm{\θ}}{2}\right)}}\right|,$ Realize the adjustment of described micro-band across the degree of coupling of directional coupler;

Wherein, k is the degree of coupling, the Z of described micro-band across directional coupler _cefor the even mode impedance value of described Coupled Miccrostrip Lines (2), θ be the electrical length of described Coupled Miccrostrip Lines (2), ω=2 π f, f be for described micro-band is across inductance value, the Z of the centre frequency of directional coupler, the tuning coil of L included by the tuning branch road of the degree of coupling (10) that is connected with the first power supply circuits (5) or the second power supply circuits (6) ₀it is 50 ohm.