Power divider with an integrated filter

Abstract

It is an electromagnetic power divider comprising first port (1), second port (2), third port (3), substrate (S), conductive circuit elements on the upper surface of the substrate (S), conductive grounding layer on the lower surface of the substrate (S); the conductive circuit elements 5 include: input line (IL) connected to the first port (1); two output lines (OL), one connected to the second port (2) the other to the third port (3); branches (B) forming a quadrilateral area (A); Wilkinson power divider (10) having resistance (R) located between the branches (B) and conductive layer (CL) positioned such that there is an insulating space (G) between the branches (B) and nested complementary split ring resonator (20) having insulating outer ring 0 (OR) and insulating inner ring (IR) arranged and positioned inside the conductive layer (CL) for providing the desired filtering function.

Description

[0001] POWER DIVIDER WITH AN INTEGRATED FILTER

[0002] Relevant Technical Field

[0003] The present invention relates to a power divider with an integrated filter, which is developed specifically for use in nano-satellite communications.

[0004] Prior Art

[0005] Power dividers / combiners are widely used technologies in current communication systems, including single-frequency systems, array systems, and half-duplex Time Division Multiplexing (TDM) communication systems. In these implementations, Wilkinson power dividers (WPD) are often used to achieve satisfactory isolation. Since Wilkinson power dividers are symmetrical structures, amplitude and phase imbalances are also satisfactory.

[0006] Band-pass / band-stop filters are another important component of microwave circuits due to their ability to separate the desired frequency band. Power dividers and filters are used together in many communication systems. Similarly, there are many filter designs in the state of the art.

[0007] In modern communication systems; filters with high selectivity, small size and strong reduction effect in stop band are needed. Metamaterials that show negative permittivity and permeability at resonance frequency generally consist of resonators arranged on substrates and whose resonance frequencies can be determined. In the state of the art, there are various metamaterial implementations with different geometries. One of these, split ring resonators (SRR), typically consist of thin metal rings arranged on an insulating substrate and have a specific resonance frequency. Split ring resonators are designed to control and direct electromagnetic wave interactions in a special way and are seen to be used in band-pass filters, band-stop filters and sensor applications. The quality factor of the filters is important for narrow band applications. However, in sensor applications, the increase in sensitivity together with the increasing quality factor makes split ring resonators unsuitable in terms of their size. In order to provide a solution to the mentioned problem, complementary split ring resonators have been developed. Complementary split ring resonators consist of insulating strips in the form of a ring surrounded by a conductive material. These structures are used to obtain more complex electromagnetic properties and are generally preferred in filtering and wave guiding applications.

[0008] Nano satellites contain small electronic boards of approximately 10 cm2 due to size constraints, which makes size a fundamental criterion for nano satellite design. These satellites use various communication bands such as Telemetry & Tele-command, data link, inter-satellite link and so on. In some scenarios, multiple functions need to be performed together and in this case, there may be interference between the communication links. Some communication bands used may be close to each other and therefore, the use of high quality band-stop filters or band-pass filters is required. Therefore, two of the important components forthese satellites are power dividers and band-pass I band-stop filters. Therefore, there is a need for development regarding the use of these components in nano satellites in accordance with the size and weight constraints.

[0009] Integrating power dividers and band-pass / stop filters to perform both dividing and filtering operations on an incoming signal provides advantages such as low insertion loss, small size and weight, and low cost, and is a necessity especially for systems with size constraints such as nano satellites.

[0010] Object of the invention

[0011] The object of the present invention is to develop an integrated structure having both filtering and power dividing function.

[0012] Another object of the present invention is to develop an integrated structure; having small dimensions and low weight which provides both power splitting and filtering functions and which is suitable for use in applications where size constraints are important, such as nano satellites.

[0013] Definition of the Figures

[0014] Exemplary applications of the power divider with integrated filter developed with the present invention are shown in the attached figures and from these figures;

[0015] Figure 1 ; is an illustration of the Wilkinson power divider included in the structure according to the present invention.

[0016] Figure 2; is an illustration of the complementary split ring resonator included in the structure according to present the invention.

[0017] Figure 3; is an illustration of the power divider having an integrated filter according to the present invention.

[0018] Figure 4; is an illustration of the dimensions of the power divider having an integrated filter according to the present invention. Figure 5; is the graphical representation of the S21 and S31 full wave simulation and measurement results of the power divider having an integrated filter according to the present invention.

[0019] Figure 6; is the graphical representation of the a) amplitude, b) phase imbalance measurement results of the power divider having an integrated filter according to the present invention.

[0020] Figure 7; is the graphical representation of full wave simulation results regarding the permeability of the power divider having an integrated filter according to the present invention.

[0021] The elements in the figures are numbered one by one and the correspondences of these numbers are given below:

[0022] First port (1)

[0023] Second port (2)

[0024] Third port (3)

[0025] Input line (IL)

[0026] Output line (OL)

[0027] Branch (B)

[0028] Substrate (S)

[0029] Quadrilateral area (A)

[0030] Resistance (R)

[0031] Wilkinson power divider (10)

[0032] Insulating space (G)

[0033] Conductive layer (CL)

[0034] Complementary split ring resonator (20)

[0035] Extension (L)

[0036] Outer ring (OR)

[0037] Inner ring (IR)

[0038] First gap (11)

[0039] Second gap (12)

[0040] Line width (W1)

[0041] Branch width (W2)

[0042] Horizontal side length (A1)

[0043] Vertical side length (A2)

[0044] Outer ring edge length (D) Extension length (L1)

[0045] Distance between outer ring and inner ring (M)

[0046] First gap and second gap distance (X)

[0047] Inner ring and outer ring width (W3)

[0048] Insulating space distance (XG)

[0049] S21 measured (5)

[0050] S31 measured (6)

[0051] S21 full wave simulation (7)

[0052] S31 full wave simulation (8)

[0053] Description of the Invention

[0054] With the present invention, an electromagnetic power divider with an integrated filter is developed to solve the above-mentioned technical problems, which enables both power division and filtering operations to be applied to an input signal and is suitable for use in communication systems. The power divider in question comprises a first port (1) arranged as the input port, a second port (2) and a third port (3) arranged as the output ports, an insulating substrate (S), conductive circuit elements located on an upper surface of the substrate (S), and a conductive grounding layer (not shown in the figures) located on a lower surface of the substrate (S); wherein the said conductive circuit elements located on the said upper surface comprises: a Wilkinson power divider (10) comprising; an input line (IL) connected to the said first port (1);

[0055] - two output lines (OL), one connected to said second port (2), the other connected to said third port (3);

[0056] - two branches (B) extending oppositely and symmetrically to form a quadrilateral area (A), connecting the input line (IL) to the said output lines (OL) a resistance (R) located between the said branches (B) at the point where they are connected to the output lines (OL) and a nested, complementary split-ring resonator (20) comprising: a conductive layer (CL) positioned in the said quadrilateral area (A) with an insulating space (G) between itself and the said branches (B) and an insulating outer ring (OR) and an insulating inner ring (IR) nested within each other positioned inside said conductive layer (CL) so as to be surrounded by said conductive layer (CL) and arranged in a manner to provide the desired filtering function and. In an exemplary embodiment of the invention, an input signal coming from the first port (1) passes through the input line (IL); is divided into two by the said branches (B) and comes to the output lines (OL) and is transmitted to the said second port (2) and third port (3), arranged as output ports. The signal, which is subjected to power division by the Wilkinson power divider (10), is also subjected to filtering by the complementary split ring resonator (20) located in the middle section while passing through the said branches (B). Thus, it is ensured that the output signals received from the output ports (2, 3) are subjected to both power splitting and filtering processes. In the structure in question, the conductive areas on the upper surface of the substrate (S) represent the areas where there is a conductive (copper) microstrip layer on the substrate (S) surface; the insulating areas represent the areas where there is no conductive microstrip layer on the upper surface of the substrate (S).

[0057] The structure of the Wilkinson power divider (10) in question is shown in Figure 1 . As shown in Figure 1 , the conductive input line (IL) arranged on the insulating substrate (S) connects the first port (1), arranged as the input port, to the second and third ports (2, 3), arranged as the output ports. The input line (IL) is divided into the said branches (B), which have the same length and width as each other, extending mutually and symmetrically and forming a quadrilateral shaped area (A) between them.

[0058] In a preferred embodiment of the invention, the said complementary split ring resonator (20) is arranged to exhibit a notch filter function and preferably comprises the following which are located in the inner part of the conductive layer (CL):

[0059] - the said outer ring (OR) in a square form, comprising a first gap (11) aligned with the first port (1) and an extension (L) extending from each end of the first gap (1 1) towards the inner part of said outer ring (OR);

[0060] - the said inner ring (IR) forming a U form surrounding said extensions (L) and located inside of the said outer ring (OR), which inner ring (IR) comprises a second gap (12) on the opposite side of the said first gap (11) and in line with the first gap (11) located on the base of the U form.

[0061] An exemplary representation of the complementary split ring resonator in question is given in Figure 2. In Figure 2, the area shaded with oblique lines shows the insulating part, that is, the parts where there is no conductive layer on the upper surface of the substrate (S), and the white area shows the parts covered with the conductive layer on the upper surface of the substrate (S). In Figure 3, the power divider structure which is the subject of the invention is shown as a whole. As seen in Figure 3, the complementary split ring resonator (20) is positioned in the quadrilateral area (A) located in the middle part of the Wilkinson power divider (10) with an insulating space (G) between the mentioned branches (B). Since the complementary split ring resonator (20) is surrounded by the mentioned Wilkinson power divider (10) on four sides, the resonance frequency must be adjusted in accordance with this structure. In order for the notch filter to provide good attenuating, the said insulating space (G) is formed.

[0062] In the preferred embodiments of the said structure, the distances (X) of the said first gap (11) and second gap (12); the widths (W3) of the said outer ring and inner ring and the line widths (W1) of each of the said input line (IL) and output lines (OL) are equal to each other, respectively.

[0063] In a preferred embodiment of the invention, the dimensions of the said circuit elements have been optimized to obtain the best performance. The markings related to the said dimensions are shown in Figure 4 and the relevant dimensions are given in Table 1 .

[0064] Tablo - 1

[0065] As indicated in the table and figures, the first gap (11) contained in the outer ring (OR) and the second gap (12) contained in the inner ring (IR) of the complementary split ring resonator (20) have a gap distance (X) that is equal to each other and preferably 0,6 mm. The outer ring (OR) and the inner ring (IR) have an equal width (W3) and this width is preferably 0,6 mm. While the input line (IL) and output lines (OL) have a line width (W1) of 2,42 mm, the width (W2) of the branches (B) is 1 ,39 mm. The branch width (W2) specified here is the width of the branches (B) in the parts parallel to the edges of the quadrilateral area (A), and the branch width (W2) changes at the corners of the quadrilateral area (A). The horizontal side length (A1) of the conductive layer (CL), which is positioned in the quadrilateral area (A) in the middle part of the branches (B) with the said insulating space (G) between itself and the branches (B), is 12,38 mm; the vertical side length (A2) is 15,28 mm. The horizontal edge herein is defined as the edges extending parallel to the input line (IL) and the vertical edge as the edges extending perpendicular to the input line (IL). The said insulating space (G) preferably has an insulating space distance (XG) between the said complementary split ring resonator (20) and the Wilkinson power divider (10) which is equal to each other at every point and the said insulating space distance (XG) is preferably 0,11 mm. The outer ring (OR) has a square form including the said first gap (11) and the said extensions (L) extending from the first gap (11) towards the inner parts of the outer ring (OR) and the length (D) of one side of this square form is 9,43 mm. The length (L1) of the said extensions is 3 mm. The distance (M) between the said outer ring (OR) and the inner ring (IR) is 0,85 mm.

[0066] The full wave simulation and measurement results of the inventive structure, where the complementary split ring resonator (20) is placed inside the Wilkinson power divider (10) with the mentioned insulating space (G) between the two units, regarding the pass band loss and unwanted band attenuation level are shown in the graph in Figure 5. In the said graph, the measurement results of the S21 and S31 values and the full wave simulation results are located on the same graph. The horizontal axis of the said graph gives the frequency value in gigahertz unit, and the vertical axis gives the decibel value. S21 shows the signal coming in from the first port (1) and going out of the second port (2), and S31 shows the signal coming in from the first port (1) and going out from the third port (3). In the said graph, it is seen that the S21 measured (5), S31 measured (6), S21 full wave simulation (7) and S31 full wave simulation (8) curves overlap, therefore the simulation results and measurement results regarding the S21 and S31 values overlap. As shown in the graph, the power divider of the invention whose dimensions are given above shows a notch filter function that attenuates the 2202-2208 MHz range. The results in Figure 5 clearly show that 17dB attenuation is achieved in the data link band with only 1dB of main line loss.

[0067] In addition, as shown in Figure 6, the amplitude and phase imbalances of the structure which is the subject of the invention give satisfactory results. The graph in Figure 6a shows the frequency (GHz) value on the horizontal axis and the amplitude (dB) value on the vertical axis for the S21 measured (5) and S31 measured (6) curves. The graph in Figure 6b shows the frequency (GHz) value on the horizontal axis and the angle (°) value on the vertical axis for the S21 measured (5) and S31 measured (6) curves. Since split ring resonators can create negative permeability at the resonance frequency, the epsilon value of the structure in question was also examined and is shown in Figure 7. The graph in Figure 7 shows the full wave simulation results regarding the permeability of the power divider with an integrated filter which is the subject of the invention, and the horizontal axis of the graph shows the frequency (GHz) and the vertical axis shows the epsilon (cr) values.

[0068] The present invention provides a power divider with an integrated filter, which is designed to be suitable for use in satellite communications and provides power dividing and filtering functions simultaneously. This structure, obtained by integrating a complementary split-ring resonator into the Wilkinson power divider, enables simultaneous dividing / combining and filtering operations.

[0069] The structure in question is used in a preferred application to perform power division in the inter-satellite connection payload of nano satellites while at the same time weakening the data link band. The design in question has been developed to be used in the simultaneous communication of data line (2202-2208 MHz) and intersatellite connection (2288-2290 MHz) lines. In this direction, the power divider in question used in the intersatellite connection payload, performs power division for the antenna array while weakening the data link communication band. Thus, it is ensured that the inter-satellite connection link (space to space) and the data link (space to ground surface) can be operated simultaneously in the same frequency band on a nano satellite without compromising on size constraints.

Claims

CLAIMS1. An electromagnetic power divider comprising a first port (1) arranged as input port, a second port (2) and a third port (3) arranged as output ports, an insulating substrate (S), conductive circuit elements located on an upper surface of the substrate (S), a conductive grounding layer located on a lower surface of the substrate (S) wherein, the conductive circuit elements located on the upper surface comprise: a Wilkinson power divider (10) having: an input line (IL) connected to the said first port (1);- two output lines (OL), one connected to said second port (2), the other connected to said third port (3);- two branches (B) extending oppositely and symmetrically to form a quadrilateral area (A), connecting the input line (IL) to the said output lines (OL) a resistance (R) located between the said branches (B) at the point where they are connected to the output lines (OL) and a nested, complementary split ring resonator (20) having: a conductive layer (CL) positioned in the said quadrilateral area (A) with an insulating space (G) between itself and the said branches (B) and an insulating outer ring (OR) and an insulating inner ring (IR) positioned inside said conductive layer (CL) nested within each other, so as to be surrounded by said conductive layer (CL) and arranged in a manner to provide the desired filtering function.

2. An electromagnetic power divider in accordance with Claim 1 wherein the said complementary split ring resonator (20) comprises the following, which are located in the inner part of the conductive layer (CL):- the said outer ring (OR) in a square form, comprising a first gap (11) aligned with the first port (1) and an extension (L) extending from each end of the first gap (11) towards the inner part of said outer ring (OR); and- the said inner ring (IR) forming a U form surrounding said extensions (L) and located inside of the said outer ring (OR), which inner ring (IR) comprises a second gap (12) on the opposite side of the said first gap (11) and in line with the first gap (11) located on the base of the U form.

3. An electromagnetic power divider in accordance with any of the preceding claims, comprising the said complementary split ring resonator (20) arranged to perform notch filter function.

4. An electromagnetic power divider in accordance with any of the preceding claims, comprising the said complementary split ring resonator (20) arranged to attenuate 2202-2208 MHz range.

5. An electromagnetic power divider in accordance with any of Claims 2 to 4 comprising the said first gap (1 1) and the said second gap (12) having a same first gap and second gap distance (X).

6. An electromagnetic power divider in accordance with any of the preceding claims, comprising said outer ring (OR) and inner ring (IR) whose widths are equal to each other.

7. An electromagnetic power divider in accordance with any of the preceding claims, comprising said input line (IL) and output lines (OL), each of which has a line width (W1) equal to each other.

8. An electromagnetic power divider in accordance with any of the preceding claims, comprising said insulating space (G) between the complementary split ring resonator (20) and the Wilkinson power divider (10) having an insulating space distance (XG) equal to each other at every point.

9. An electromagnetic power divider in accordance with any of claims 2 to 7 comprising:- the said first gap (11) and second gap (12) each of which having a gap distance (X) of 0,6 mm;- the said outer ring (OR) and inner ring (IR) each of which having a width (W3) of 0,6 mm;- the said input line (IL) and output lines (OL) each of which having a line width (W1) of 2,42 mm;- the said branches (B) each of which having a branch width (W2) of 1 ,39mm.- the said conductive layer (CL) having a horizontal side length (A1) of 12,38 mm, and a vertical side length (A2) of 15,28 mm;- the said insulating space (G) having an insulating space distance (XG) of 0.11 mm;- the said outer ring (OR) having an outer ring edge length (D) of 9,43mm.

10. A satellite comprising at least one inter-satellite link payload, at least one data link payload, at least one antenna array and at least one electromagnetic power divider according to any of the preceding claims arranged to said inter-satellite link payload toperform power splitting for said antenna array while at the same time attenuating the communication band of the link payload.

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