Microstrip transmission line

Abstract

The invention discloses a microstrip transmission line, and relates to the technical field of microstrip transmission, the microstrip transmission line comprises a plurality of segments, except the segment at the central position, other segments are connected with capacitors in parallel, the segment at the central position is the (n + 1) / 2 segment, n is an odd number greater than or equal to 3, and n is the number of the segments. The microstrip transmission line provided by the invention has the advantages of small impedance and large transmission power.

Description

Technical Field

[0001] The present invention relates to the technical field of microstrip transmission, and in particular to a microstrip transmission line. Background Art

[0002] Microstrip transmission lines are a type of microwave integrated transmission line that is widely used, especially in microwave integrated circuits. The power that a microstrip transmission line can transmit and the impedance during the transmission process are the most important performance indicators for microstrip transmission lines. Therefore, when the size of the microstrip line increases, how to keep the impedance unchanged while increasing the transmission power is an urgent problem to be solved in the field of microstrip transmission technology. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides a microstrip transmission line having the advantages of small impedance and large transmission power.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A microstrip transmission line includes a plurality of microstrip transmission baseline segments. Except for a microstrip transmission baseline located at a central position, other segments are connected in parallel with capacitors. The segment located at the central position is the (n+1) / 2th segment, n≥3 and n is an odd number, wherein n is the number of segments.

[0006] Optionally, the microstrip transmission baseline length of the parallel capacitor segment is symmetrical with the segment located at the central position as the center.

[0007] Optionally, the microstrip transmission baseline segments of the parallel capacitors are symmetrical with the capacitance of the parallel capacitors being centered at the segment located at the center.

[0008] Optionally, each microstrip transmission baseline segment has an equal width.

[0009] Optionally, the microstrip transmission baseline has a dielectric substrate, the microstrip transmission baseline is laid on the dielectric substrate, and the unit length parallel capacitance and unit length series inductance of each section of the microstrip transmission baseline satisfy the following formula:

[0010]

[0011] Among them, C 0 is the shunt capacitance per unit length of the microstrip transmission line, L 0 is the unit length series inductance of the microstrip transmission line, W is the width of the microstrip transmission line, h is the thickness of the dielectric substrate, ε r is the relative dielectric constant of the dielectric substrate, ε re is the effective relative dielectric constant of the dielectric substrate, v 0 is the speed of light in a vacuum.

[0012] Optionally, the characteristic impedance of the microstrip transmission baseline is:

[0013]

[0014] or

[0015]

[0016] Among them, Z 0 is the characteristic impedance of the microstrip transmission baseline.

[0017] Optionally, when the characteristic impedance of the microstrip transmission baseline and the relative dielectric constant of the dielectric substrate are fixed, the width of the microstrip transmission baseline and the thickness of the dielectric substrate satisfy the following formula:

[0018]

[0019] Among them, Z 0 ' is the characteristic impedance of the fixed microstrip transmission baseline, ε r ' is the relative dielectric constant of the fixed dielectric substrate, a and b are transition parameters in the calculation process.

[0020] Optionally, the microstrip transmission baseline may be equivalent to a T-type network. When it is equivalent to a T-type network, the microstrip transmission baseline satisfies the following formula:

[0021]

[0022] Among them, Z 1 and Z 2 is the impedance of the series arm in the T-type network, Z 3 is the impedance of the parallel arm in the T-type network, β is the propagation function of the microstrip transmission baseline, l is the line length of the microstrip transmission baseline, and j is the imaginary unit;

[0023] Or satisfy the following formula:

[0024]

[0025] Among them, X L is the series reactance, B C is the parallel susceptance.

[0026] Optionally, starting from the terminal of the microstrip transmission line, the impedance of the capacitor connected in parallel to each segment is:

[0027]

[0028] in, is the impedance of the capacitor connected in parallel with the segment, C kis the capacitance of the capacitor connected in parallel with the segment, and w is the angular frequency;

[0029] The input impedance of each segment is:

[0030]

[0031] in, The input impedance of each segment is l k is the length of each segment;

[0032] The equivalent input impedance of each segment superimposed on all the previous segments is:

[0033]

[0034] in, For each segment, add the equivalent input impedance of all the segments preceding it.

[0035] The technical solution provided by the present invention has the following beneficial effects:

[0036] The technical solution provided by the present invention increases the power that can be transmitted by the microstrip transmission line while maintaining the thickness of the microstrip transmission line unchanged and increasing the width of the microstrip transmission line. The microstrip transmission line can be equivalent to an inductive impedance or a capacitive impedance. When the line width of the microstrip transmission line increases, the power that can be sustained also increases accordingly. From the equivalent T-type network, it can be seen that its characteristic impedance is reduced, and the total equivalent input impedance of the microstrip line is changed by adjusting the parallel capacitor and the length of each transmission line. Finally, the impedance is kept unchanged while increasing the transmission power of the microstrip line.

[0037] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. The best embodiments or means of the present invention will be described in detail in conjunction with the drawings, but they are not intended to limit the technical solutions of the present invention. In addition, there are multiple features, elements, and components that appear in each of the following texts and drawings, and different symbols or numbers are marked for convenience, but they all represent components with the same or similar structures or functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be further described below in conjunction with the accompanying drawings:

[0039] Figure 1 and Figure 2 is a schematic diagram of an embodiment of the present invention;

[0040] Figure 3 It is a partial enlarged view of an embodiment of the present invention;

[0041] Figure 4 is a cross-sectional view of an embodiment of the present invention;

[0042] Figure 5 A circuit diagram equivalent to a T-type network in an embodiment of the present invention;

[0043] Figure 6 The circuit diagram of the embodiment of the present invention is a series inductor and a parallel capacitor equivalent to a T-type network.

[0044] Among them, 1-microstrip transmission line, 2-dielectric substrate, 3-grounding plate. DETAILED DESCRIPTION

[0045] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments in the implementation manner are intended to be used to explain the present invention and should not be construed as limiting the present invention.

[0046] References in this specification to "one embodiment" or "an example" or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment itself may be included in at least one embodiment of the present patent disclosure. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0047] Example:

[0048] As one aspect of the present invention, the present embodiment provides a microstrip transmission line, including a plurality of microstrip transmission baseline segments, each of which has an equal width. Except for the segment located in the center, all other segments are connected in parallel with capacitors, and the capacitance of the capacitors connected in parallel is symmetrical with the segment located in the center as the center, and the length of the microstrip transmission baseline segments connected in parallel with capacitors is symmetrical with the segment located in the center as the center. The segment located in the center is the (n+1) / 2 segment, n≥3 and n is an odd number, where n is the number of segments.

[0049] like Figure 1 and Figure 2 As shown, this embodiment is described in detail by taking a microstrip transmission line divided into 7 sections as an example. The microstrip transmission line divided into 7 sections provided in this embodiment has a total length of l and a characteristic impedance of Z 0 , the propagation function is β, and the width of each segment is equal. The segments located in the center are (1+7) / 2=4 segments, that is, the 4th segment is the segment in the center. In this embodiment, starting from the terminal of the microstrip transmission line, the length of each segment is l 1 , l 2 , l 3 , l 4 , l 5 , l 6 , l 7 Except for the fourth segment, the lengths of the other segments are symmetrical with respect to the segment in the center, i.e.1 = l 7 , l 2 = l 6 , l 3 = l 5 Except for the fourth segment, other segments are connected with capacitors in parallel, and the capacitance of the capacitors in parallel in other segments is symmetrical with the segment located in the central position as the center, that is, the first segment is connected with capacitor C1 in parallel, the second segment is connected with capacitor C2 in parallel, the third segment is connected with capacitor C3 in parallel, the fifth segment is connected with capacitor C5, C5=C3, the sixth segment is connected with capacitor C6, C6=C2, and the seventh segment is connected with capacitor C7, C7=C1.

[0050] like Figure 3 and Figure 4 As shown, the microstrip transmission line 1 provided in this embodiment has a dielectric substrate 2, the microstrip transmission line 1 is laid on the dielectric substrate 2, and the dielectric substrate 2 is laid on the grounding plate 3. Its characteristic impedance Z 0 for:

[0051]

[0052] The unit length parallel capacitance and unit length series inductance of each segmented microstrip transmission baseline satisfy the following formula:

[0053]

[0054]

[0055] Among them, C 0 is the shunt capacitance per unit length of the microstrip transmission line, L 0 is the unit length series inductance of the microstrip transmission line, W is the width of the microstrip transmission line, h is the thickness of the dielectric substrate, ε r is the relative dielectric constant of the dielectric substrate, ε re is the effective relative dielectric constant of the dielectric substrate, v 0 is the speed of light in a vacuum.

[0056] Substituting formula (2) and formula (3) into formula (1), we can get the characteristic impedance Z of the microstrip transmission line 1: 0 With the width W of the microstrip transmission line 1 and the thickness h of the dielectric substrate 2, the effective relative dielectric constant ε of the dielectric substrate 2 re Satisfies the following formula:

[0057]

[0058] In this embodiment, the characteristic impedance of the microstrip transmission baseline and the relative dielectric constant of the dielectric substrate may also be a given value or a fixed value. In this case, the width of the microstrip transmission baseline and the thickness of the dielectric substrate satisfy the following formula:

[0059]

[0060] Among them, Z 0 ' is the characteristic impedance of the fixed microstrip transmission baseline, ε r ' is the relative dielectric constant of the fixed dielectric substrate, a and b are transition parameters in the calculation process.

[0061] like Figure 5 and Figure 6 As shown, the microstrip transmission baseline provided in this embodiment can be equivalent to a T-type network. When it is equivalent to a T-type network, the microstrip transmission baseline satisfies the following formula:

[0062]

[0063] Among them, Z 1 and Z 2 is the impedance of the series arm in the T-type network, Z 3 is the impedance of the parallel arm in the T-type network, β is the propagation function of the microstrip transmission baseline, l is the line length of the microstrip transmission baseline, and j is the imaginary unit;

[0064] Or satisfy the following formula:

[0065]

[0066] Among them, X L is the series reactance, B C is the parallel susceptance.

[0067] In this embodiment, the impedance of the capacitor connected in parallel to each microstrip transmission baseline segment is:

[0068]

[0069] in, is the impedance of the capacitor connected in parallel with the segment, C k is the capacitance of the capacitor connected in parallel with the segment, j is the imaginary unit, and w is the angular frequency;

[0070] The input impedance of each segment is:

[0071]

[0072] in, The input impedance of each segment is l k is the length of each segment;

[0073] The equivalent input impedance of each segment superimposed on all the previous segments is:

[0074]

[0075] in, For each segment, add the equivalent input impedance of all the segments preceding it.

[0076] Specifically in this embodiment, the input impedance is calculated from the rightmost end, considering that the first segment has an open terminal, and the input impedance

[0077]

[0078] The impedance of the first segment parallel capacitor C1 is:

[0079]

[0080] The equivalent input impedance Z of the first segment after the parallel capacitor C1 in1 for:

[0081]

[0082] Equivalent input impedance Z in1 is the load at the end of the second segment, and the input impedance of the second segment is obtained. for:

[0083]

[0084] The impedance of the second segment parallel capacitor C2 is:

[0085]

[0086] The total equivalent input impedance Z after the second segment of the parallel capacitor C2 and the first segment of the parallel capacitor C1 in2 for:

[0087]

[0088] Equivalent input impedance Z in2 is the load at the end of the third segment, and the input impedance of the third segment is obtained. for:

[0089]

[0090] The impedance of the third segment parallel capacitor C3 is:

[0091]

[0092] The third segment of the parallel capacitor C3, the second segment of the parallel capacitor C2, the first segment of the parallel capacitor C1, the total equivalent input impedance Z in3 for:

[0093]

[0094] Equivalent input impedance Z in3 is the load at the end of the fourth segment; the fourth segment, the third segment of the parallel capacitor C3, the second segment of the parallel capacitor C2, and the first segment of the parallel capacitor C1, the total equivalent input impedance Z in4 for:

[0095]

[0096] Equivalent input impedance Z in4 is the load at the end of the fifth segment, and the input impedance of the fifth segment is obtained. for:

[0097]

[0098] The impedance of the fifth segmented parallel capacitor C5 is the same as the impedance of the third segmented parallel capacitor C3, and will not be described again here;

[0099] The fifth segment of the parallel capacitor C5, the fourth segment, the third segment of the parallel capacitor C3, the second segment of the parallel capacitor C2, the first segment of the parallel capacitor C1, the total equivalent input impedance Z in5 for:

[0100]

[0101] Equivalent input impedance Z in5 is the load at the end of the sixth segment, and the input impedance of the sixth segment is obtained. for:

[0102]

[0103] The impedance of the sixth segmented parallel capacitor C6 is the same as the impedance of the second segmented parallel capacitor C2, and will not be described again here;

[0104] The sixth segment of the parallel capacitor C6, the fifth segment of the parallel capacitor C5, the fourth segment, the third segment of the parallel capacitor C3, the second segment of the parallel capacitor C2, the first segment of the parallel capacitor C1, the total equivalent input impedance Z in6 for:

[0105]

[0106] Equivalent input impedance Z in6 is the load at the end of the seventh segment, and the input impedance of the seventh segment is obtained. for:

[0107]

[0108] The impedance of the seventh segmented parallel capacitor C7 is the same as the impedance of the first segmented parallel capacitor C1, and will not be described again here;

[0109] The seventh segment of the parallel capacitor C7 and the sixth segment of the parallel capacitor C6, the fifth segment of the parallel capacitor C5, the fourth segment, the third segment of the parallel capacitor C3, the second segment of the parallel capacitor C2, the first segment of the parallel capacitor C1, the total equivalent input impedance Z in7 for:

[0110]

[0111] When the characteristic impedance Z of the microstrip transmission line 0 When the propagation constant β and the angular frequency w are determined, the total equivalent input impedance of the microstrip transmission line can be adjusted by parameters such as the length of each microstrip transmission baseline segment, the capacitance of the capacitor in parallel with the segment, etc.

[0112] The technical solution provided in this embodiment increases the power that can be transmitted by the microstrip transmission line while keeping the thickness of the microstrip transmission line unchanged and increasing the width of the microstrip transmission line. The microstrip transmission line can be equivalent to an inductive impedance or a capacitive impedance. When the line width of the microstrip transmission line increases, the power that can be sustained also increases accordingly. From the equivalent T-type network, it can be seen that its characteristic impedance is reduced. The total equivalent input impedance of the microstrip line is changed by adjusting the parallel capacitor and the length of each transmission line segment.

[0113] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A microstrip transmission line, characterized in that: The microstrip transmission line includes several segmented microstrip transmission baselines. Except for the microstrip transmission baseline located in the central position, other segments are connected in parallel with capacitors. The segment located in the central position is the (n+1) / 2th segment, n≥3 and n is an odd number, where n is the number of segments.

2. The microstrip transmission line according to claim 1, characterized in that: The microstrip transmission baseline length of the parallel capacitor segment is symmetrical around the segment located in the center.

3. The microstrip transmission line according to claim 1, characterized in that: The capacitance of the capacitors connected in parallel is symmetrical with respect to the segment located in the center.

4. The microstrip transmission line according to claim 1, characterized in that: The width of each microstrip transmission baseline segment is equal.

5. The microstrip transmission line according to claims 1 to 4, characterized in that: The microstrip transmission baseline has a dielectric substrate, the microstrip transmission baseline is laid on the dielectric substrate, and the unit length parallel capacitance and unit length series inductance of each section of the microstrip transmission baseline satisfy the following formula: Where C0 is the parallel capacitance per unit length of the microstrip transmission baseline, L0 is the series inductance per unit length of the microstrip transmission baseline, W is the width of the microstrip transmission baseline, h is the thickness of the dielectric substrate, ε r is the relative dielectric constant of the dielectric substrate, ε re is the effective relative dielectric constant of the dielectric substrate, and v0 is the speed of light in a vacuum.

6. The microstrip transmission line according to claim 5, characterized in that: The characteristic impedance of the microstrip transmission line is: or Wherein, Z0 is the characteristic impedance of the microstrip transmission line.

7. The microstrip transmission line according to claim 5, characterized in that: When the characteristic impedance of the microstrip transmission baseline and the relative dielectric constant of the dielectric substrate are fixed, the width of the microstrip transmission baseline and the thickness of the dielectric substrate satisfy the following formula: Where Z0' is the characteristic impedance of the fixed microstrip transmission line, ε r ' is the relative dielectric constant of the fixed dielectric substrate, a and b are transition parameters in the calculation process.

8. The microstrip transmission line according to claim 5, characterized in that: The microstrip transmission baseline can be equivalent to a T-type network. When it is equivalent to a T-type network, the microstrip transmission baseline satisfies the following formula: Wherein, Z1 and Z2 are the impedances of the series arms in the T-type network, Z3 is the impedance of the parallel arm in the T-type network, β is the propagation function of the microstrip transmission baseline, l is the line length of the microstrip transmission baseline, and j is the imaginary unit; Or satisfy the following formula: Among them, X L is the series reactance, B C is the parallel susceptance.

9. The microstrip transmission line according to claims 1 to 8, characterized in that: Starting from the terminal of the microstrip transmission line, the impedance of the capacitor connected in parallel to each microstrip transmission line is: Among them, Z Ck is the impedance of the capacitor connected in parallel with the segment, C k is the capacitance of the capacitor connected in parallel with the segment, and w is the angular frequency; The input impedance of each segment is: Among them, Z lk The input impedance of each segment is l k is the length of each segment; The equivalent input impedance of each segment superimposed on all the previous segments is: Among them, Z ink For each segment, add the equivalent input impedance of all the segments preceding it.

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