Novel dual-frequency dual-circularly polarized satellite antenna
The novel dual-frequency dual-circular polarization satellite antenna, with its nested dual-pattern structure and air layer design, solves the problem that existing satellite antennas cannot meet the needs of multiple services. It achieves dual-band coverage and improved circular polarization performance, enhances signal stability and anti-interference capabilities, and meets the low power consumption requirements of miniaturized satellite platforms.
Patent Information
- Application Number
- CN202511102275.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-07
- Publication Date
- 2025-11-07
AI Technical Summary
Existing satellite antenna designs cannot meet the requirements of simultaneously carrying multiple services. Single-band antennas cannot cover multiple frequency bands. Multi-layer stacked structures increase thickness and weight. Traditional microstrip antennas have low gain and are susceptible to multipath reflection interference. Complex feed network designs are difficult to be compatible with low power consumption requirements.
The system employs a nested dual-surface structure. The outer rectangular surface mount is loaded with long and short branches to achieve left-hand circular polarization, while the inner circular surface mount has rectangular slots to achieve right-hand circular polarization. An air layer is loaded between the dielectric substrate and the ground plane. The system is fed coaxially from a single feed point with optimized feed position. The circular polarization axial ratio and gain are optimized by adjusting key parameters.
It achieves dual-band coverage of L and S bands, improves the circular polarization characteristics and gain of the antenna, reduces dielectric loss, simplifies structural design, adapts to miniaturized satellite platforms, and reduces power consumption.
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Figure CN120914487A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of satellite antennas, in particular to a new type of dual-frequency dual-circularly polarized satellite antenna. BACKGROUND
[0002] In the field of satellite communication, satellites need to carry multiple services such as telemetry, data transmission, broadband communication, and satellite television signal transmission at the same time, which requires the antenna to cover multiple frequency bands to meet diversified needs. Due to the high-speed movement of low-orbit satellites in the L-band, the relative position and attitude of the ground station are constantly changing, and the antenna needs to reduce signal fading to maintain a smooth communication link. Satellite television signal transmission in the C-band needs to cope with factors such as building obstruction and atmospheric fluctuations to ensure effective coverage of signals in complex environments and different weather conditions. These scenarios have clear requirements for the frequency band coverage, polarization performance, gain, and anti-interference capability of satellite antennas.
[0003] In existing satellite antennas, traditional designs are mostly single-band structures that can only work in a single frequency band such as L or S. Dual-frequency circularly polarized antennas often use a multi-layer stacking structure to achieve dual-frequency functionality. Microstrip antennas mostly rely on a single patch for signal processing. Some circularly polarized antennas achieve circular polarization performance through complex feed networks. These designs meet the basic needs of satellite communication to some extent.
[0004] However, the existing technology has obvious deficiencies: single-band antennas cannot meet the needs of simultaneous carrying of multiple services, and installing multiple antennas will increase the volume and cost of the load. The multi-layer stacking of dual-frequency circularly polarized antennas increases the thickness and weight, making it difficult to adapt to small satellite platforms. Traditional microstrip antennas have low gain and are easily disturbed by multipath reflection, with significant signal fading. Circularly polarized antenna designs that rely on complex feed networks are difficult and have high power consumption, making it difficult to be compatible with the low-power requirements of satellite loads. SUMMARY
[0005] The present application provides a new type of dual-frequency dual-circularly polarized satellite antenna, aiming to improve at least one of the above technical problems.
[0006] A new type of dual-frequency dual-circularly polarized satellite antenna includes a ground plane, a single-feed point coaxial line, a dielectric substrate, and a metal patch bonded to the dielectric substrate. A gap layer is provided between the ground plane and the dielectric substrate.
[0007] The single-feed point coaxial line passes through the gap layer and the dielectric substrate to electrically connect the ground plane and the metal patch.
[0008] The metal patch comprises a circular patch of an inner layer, and a rectangular patch of an outer layer which is sleeved on the circular patch. The circular patch is provided with a rectangular slot to realize right-handed circular polarization. Two pairs of edges of the rectangular patch are respectively provided with long branches and short branches to realize left-handed circular polarization. Four corners of the rectangular patch or positions close to the four corners are electrically connected to the circular patch.
[0009] As a further optimization, the single-feed-point coaxial line is arranged on a diagonal line of the metal patch at a feed position of the metal patch. The feed position of the single-feed-point coaxial line is in the range of 17.5 mm to 18.5 mm.
[0010] As a further optimization, the pair of edges of the rectangular patch provided with the short branches are electrically connected to the circular patch at positions close to the rectangular four corners.
[0011] As a further optimization, the long branches are in the shape of a square. The ratio of the width of the long branches to the length is 1:1. The short branches are in the shape of a rectangle. The ratio of the width of the short branches to the length is 2:3. The rectangular slot is in the shape of a rectangle. The ratio of the width of the rectangular slot to the length is 4:5.
[0012] As a further optimization, the width of the long branches is in the range of 5.5 mm to 6.5 mm. The width of the short branches is in the range of 1.5 mm to 2.5 mm. The slotting depth of the rectangular slot is in the range of 3.5 mm to 4.5 mm.
[0013] As a further optimization, the gap layer is an air layer.
[0014] As a further optimization, the thickness of the gap layer is in the range of 0.5 mm to 1.5 mm.
[0015] The feed position . The width of the connection between the rectangular patch and the circular patch. The thickness of the gap layer.
[0016] As a further optimization, the rectangular patch is configured as a rectangular frame structure. The width of the frame. The width of the long branches. The length of the long branches. The width of the short branches.The length of the short branch .
[0017] As a further optimization, the width of the dielectric substrate is 120mm, the length is 120mm, and the thickness is 1.6mm. The material of the dielectric substrate is FR4, the dielectric constant is 4.4, and the loss tangent angle is 0.0015.
[0018] By adopting the technical solutions described above, the application can achieve the following technical effects: The novel dual-frequency dual-circularly polarized satellite antenna adopts an inner-outer nested dual-patch structure, the edges of the rectangular patch of the outer layer are loaded with long-short branches to realize left-handed circular polarization, and the edges of the circular patch of the inner layer are opened with rectangular slots to realize right-handed circular polarization. An air layer with a thickness of is loaded between the ground plane and the dielectric substrate to reduce loss and improve gain. Single-feed-point coaxial line feeding is adopted, and the circular polarization axial ratio is optimized by adjusting the feeding position. In addition, key parameters such as branch length and slot depth are optimized, so that the antenna has good dual-frequency coverage, circular polarization characteristics and gain performance in the L and S frequency bands. Since a single patch often cannot obtain high gain, the application can effectively reduce the dielectric loss of the medium by introducing an air layer to increase the gain of the antenna. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the specific embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.
[0020] Figure 1 is a structural schematic diagram of the novel dual-frequency dual-circularly polarized satellite antenna.
[0021] Figure 2 is a waveform diagram of the axial ratio and parameters of different frequencies and different widths of the long branch .
[0022] Figure 3 is a waveform diagram of the axial ratio and parameters of different frequencies and different widths of the short branch .
[0023] Figure 4 is a waveform diagram of the axial ratio and parameters of different frequencies and different slot depths .
[0024] Figure 5 Different frequencies and different feed locations axial ratio and Waveform of the parameters.
[0025] Figure 6 The thickness of different interstitial layers Gain and Waveform of the parameters. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.
[0027] Depend on Figure 1 As shown, this embodiment of the invention provides a novel dual-frequency dual-circular polarized satellite antenna, which includes a ground plane, a single-feed coaxial cable, a dielectric substrate, and a metal patch bonded to the dielectric substrate. A gap layer is disposed between the ground plane and the dielectric substrate. Preferably, the gap layer is an air layer.
[0028] The single feed point coaxial line passes through the gap layer and the dielectric substrate to electrically connect to the ground plane and the metal patch. Preferably, the feed position of the single feed point coaxial line to the metal patch is located on a diagonal line of the metal patch.
[0029] The metal patch includes an inner circular patch and an outer rectangular patch fitted over the circular patch. The circular patch has rectangular slots to achieve right-handed circular polarization. The rectangular patch has long and short branches on two opposite sides to achieve left-handed circular polarization. The four corners or positions near the four corners of the rectangular patch are electrically connected to the circular patch. Preferably, the opposite sides of the rectangular patch with short branches are electrically connected to the circular patch near the four corners of the rectangle.
[0030] Specifically, the final structure of the antenna is as follows: Figure 1 As shown (where the ground plane is the ground layer, the dielectric substrate is the dielectric layer, and the metal patch is the metal layer, illustrating the layered structure of the antenna).
[0031] This invention employs a nested dual-pattern structure. The outer rectangular patch has long and short stubs loaded along its edges to achieve left-hand circular polarization, while the inner circular patch has rectangular slots along its edges to achieve right-hand circular polarization. A 1mm thick air layer is added between the ground plane and the dielectric substrate to reduce loss and improve gain. A single-feed point coaxial line is used, and the circular polarization axial ratio is optimized by adjusting the feed position. Furthermore, key parameters such as stub length and slot depth are optimized, resulting in good dual-band coverage, circular polarization characteristics, and gain performance in the L and S bands. Since a single patch often struggles to achieve high gain, this embodiment effectively reduces dielectric loss by introducing an air layer, thereby increasing antenna gain.
[0032] In this embodiment, the width of the dielectric substrate 120mm, length It is 120mm thick. The thickness is 1.6 mm. The dielectric substrate is made of FR4 material with a dielectric constant of 1.6 mm. The free space wavelength is 4.4, and the loss tangent is 0.0015. C-band free space wavelength The size of the dielectric substrate is much smaller than the wavelength of the antenna. FR4 is a flame-retardant thermosetting composite material made of fiberglass cloth and epoxy resin, and is widely used in the manufacture of printed circuit boards (PCBs).
[0033] Since circular and rectangular patches can be analyzed using the characteristic mode analysis method, by controlling the radius and the side length of the rectangle, their main mode can be made to work in TM11 and TM10 modes, while other irregular shapes are difficult to analyze qualitatively using basic theory.
[0034] To achieve a compact structure and facilitate analysis, circular and rectangular patches are used for the inner and outer layers, respectively. The circular polarization is achieved using a perturbation method. Since the feed position is located diagonally, the inner perturbation structure needs to be positioned along either the X-axis or Y-axis. Figure 1 As shown, the coaxial cable passes through the ground plane and air layer, and then through the dielectric substrate to connect with the antenna patch.
[0035] This embodiment of the dual-band circularly polarized microstrip antenna involves several dimensional parameters. The radius of the inner circular patch and the side length of the outer rectangular patch determine the antenna's operating center frequency, while the 3dB axial ratio is affected by introduced perturbation structural parameters. Therefore, this embodiment will focus on analyzing several parameters affecting the antenna axial ratio. A controlled variable approach is used, scanning only the analyzed parameters while keeping other structural parameters constant to ensure more reliable parameter analysis.
[0036] Antenna radiation mechanism is analyzed using Characteristic Mode Theory (CMT). The equivalent length of the outer rectangular patch after adding stubs must meet the resonant frequency requirement. This is combined with wavelength estimation in the L-band (1.45-1.56 GHz) (free-space wavelength of the L-band). dielectric substrate Time equivalent wavelength The length of the branch needs to match the size of the patch, and the width of the long branch should be determined initially. and the width of short branches The physical dimensions range from 1 to 7 mm.
[0037] The internal circular patch operates in the C-band (2.42-2.58GHz). Based on the characteristic mode theory (CMT), the slot depth... The resonant frequency is affected by changing the equivalent radius of the patch. The free space wavelength in the C-band. dielectric substrate Time equivalent wavelength The resonant frequency of the circular surface mount master mode TM11. The model is In the formula, For the speed of light, For patch radius, The equivalent dielectric constant. The groove depth needs to be related to the radius. For matching, the initial estimated groove depth range is 1-4mm (not exceeding 15% of the radius to avoid excessive changes to the patch structure).
[0038] In radio frequency / microwave engineering, S-parameters are standard indicators characterizing the signal behavior of multiport networks. The parameter is return loss / reflection coefficient: it represents the reflection ratio of the input signal at the port and reflects the impedance matching performance between the antenna and the feed network.
[0039] Load the width of the long branch using a rectangular patch. The effects on antenna axial ratio and impedance matching are as follows: Figure 2 As shown. With the width of the long branch node As the antenna diameter increases from 4mm to 7mm, the center frequency gradually shifts to the right, but the overall... The parameters and operating bandwidth did not change significantly, indicating that the width of the long branch was relatively stable. The size of the stub has little effect on impedance matching. Regarding the antenna's axial ratio, it can be seen that as the stub length gradually increases from 4mm to 6mm, the antenna's axial ratio gradually decreases, the axial ratio bandwidth gradually increases, and the circular polarization performance gradually improves. However, when the stub length increases to 7mm, the antenna's axial ratio increases, the axial ratio bandwidth decreases, and the circular polarization performance deteriorates somewhat. This is because the excessively large stub size results in excessively long path lengths for the two orthogonal waves, causing their phase difference to deviate from 90°.
[0040] Rectangular patch loading the width of short branches The effect on antenna axial ratio and impedance matching is as follows: Figure 3 As shown. When As the antenna diameter increases from 1mm to 4mm, the center frequency shifts towards lower frequencies, with an offset of approximately 120MHz. It is worth noting that the axial ratio bandwidth parameter increases with... Size changes exhibit non-monotonic characteristics: in As the axial bandwidth increases from 1mm to 2mm, there is a certain expansion. And when... When the axial ratio bandwidth is increased to 4mm, it actually decreases.
[0041] Analysis shows that, The size variation has less than 2% impact on the antenna impedance matching characteristics (return loss < -10dB), but a larger impact on the axial ratio bandwidth. This indicates that the short stub structure mainly plays a role in the rotational phase control of the radiation field in circularly polarized antenna design, while its impact on the impedance characteristics of the feed network is relatively limited.
[0042] Groove depth of circular patch The effects of antenna axial ratio and impedance matching are as follows: Figure 4 As shown. In this embodiment, the circular patch introduces a perturbation structure through slotting, thereby affecting the phase of the two orthogonal waves to achieve circular polarization. Figure 4 The diagram shows the antenna axial ratio and slot depth from 1mm to 4mm. The curves show the parameters changing with frequency. It can be seen that as the slot depth gradually increases from 1mm to 4mm, the antenna's axial ratio remains less than -3dB, but the center frequency gradually shifts to the right. This is because the change in slot depth alters the equivalent radius of the circular patch, thus changing the antenna's resonant frequency, although it remains within the C-band.
[0043] Feed position The impact of (i.e., the distance from the single-feed coaxial line to the center of the circular patch) on the antenna axial ratio and impedance matching is as follows: Figure 5 As shown. Besides the aforementioned perturbation structures such as loaded stubs and slots affecting the antenna's circular polarization performance, the location of the feed point also influences the path difference between the two orthogonal waves, thus affecting the antenna's circular polarization performance. From... Figure 5 As can be seen, as the feed position gradually deviates from the center of the patch, the lowest point of the antenna's axial ratio shifts to the right in both frequency bands. Regarding impedance matching, when... When the antenna diameter is increased from 15mm to 17mm, the center frequency in the low-frequency band remains almost unchanged, but the resonance depth gradually increases. The resonant depth increases when the distance increases to 18mm, and the center frequency of the antenna gradually moves right at high frequency as the feed point shifts. Since the feed position has little effect on the axial ratio bandwidth of the antenna at low frequency, the axial ratio bandwidth of the antenna at high frequency The antenna has a wider axial ratio bandwidth and better resonant depth at two frequency bands.
[0044] Therefore, in the embodiment of the present application, the feed position is in the range of 17.5mm to 18.5mm. Preferably, the feed position .
[0045] Preferably, the gap layer is an air layer. The thickness of the gap layer has an effect on the impedance matching and gain of the antenna as shown in Figure 6 . In a conventional microstrip antenna, the high dielectric constant of the dielectric substrate (such as FR4 with a dielectric constant of 4.4) will bind electromagnetic field energy, resulting in about 25%-40% of the field energy propagating laterally along the substrate in the form of surface waves and dissipating. The air-dielectric composite structure formed after the introduction of air can significantly reduce the equivalent dielectric constant, so that the surface wave cutoff frequency is increased. The reduction of energy loss makes more input power converted into effective radiation power. Similarly, due to the change of the relative dielectric constant, the resonant frequency of the antenna will also change, so the effect of different thicknesses of the gap layer on the impedance matching of the antenna needs to be explored.
[0046] It can be seen from Figure 6 that the peak gain of the antenna is obviously improved by loading the air layer compared with no air layer (i.e.: ). And with the increase of the thickness of the air layer, the peak gain of the antenna is also gradually improved. At the same time, with the increase of the thickness of the air layer, the resonant point of the antenna at low frequency gradually moves right, while the resonant point at high frequency gradually moves left. However, the impedance matching of the antenna at high frequency is poor when . And compared with , the growth of the antenna gain is smaller, and the growth trend is much weaker than and , and considering the miniaturization of the antenna size. In the embodiment, the thickness of the gap layer is in the range of 0.5mm to 1.5mm, and preferably 1mm. In other embodiments, the thickness of the gap layer can be set to other thicknesses, which are not specifically limited in the present application.
[0047] The surface perturbation structure has a significant effect on the axial ratio and matching of the antenna, while the feed position of the antenna and the thickness of the air layer have little effect on the axial ratio and matching of the antenna. Therefore, the size parameters of the perturbation structure are subjected to orthogonal experiment to obtain the globally optimal size value of the perturbation structure.
[0048] Orthogonal table L16(43), i.e. 3-factor 4-level orthogonal table, is selected to determine the test factors and levels as shown in Table 1.
[0049] Table 1 Orthogonal experiment factor level table
[0050] After the orthogonal table is obtained, 16 groups of experiments are set, and the axial ratio and S parameter of the antenna at the high frequency band and the low frequency band under the orthogonal experiment size are obtained in the simulation software, as shown in Table 2.
[0051] Table 2 Orthogonal experiment analysis results
[0052] After the data of the orthogonal experiment is obtained, the range is calculated to explore the influence degree of the above structure parameters on the S parameter and the axial ratio of the antenna at the high frequency and the low frequency, as shown in Tables 3, 4, 5 and 6, which are the range values and the significance relationship of the high frequency S parameter (dB), the low frequency S parameter (dB), the high frequency axial ratio (dB) and the low frequency axial ratio (dB) in turn.
[0053] Table 3 High frequency S parameter range analysis
[0054] Table 4 Low frequency S parameter range analysis
[0055] Table 5 High frequency axial ratio range analysis
[0056] Table 6 Low frequency axial ratio range analysis
[0057] According to the above range table, for the S parameter at the high frequency, the main influencing factor is the slot depth of the internal semicircle. For the S parameter at the low frequency, the main influencing factor is the width of the short branch. The reason is that the size of the slot and the length of the branch affect the equivalent length of the external patch and the internal patch, thereby affecting the center frequency of the antenna. For the axial ratio at the high frequency and the axial ratio at the low frequency, the main influencing factors are the slot depth and the width of the long branch, and the reason is that the perturbation structure of the slot depth and the width of the long branch affects the circular polarization performance, thereby affecting the axial ratio.
[0058] In combination, the shape of the long branch is a square. The shape of the short branch is a rectangle. The ratio of the width and the length of the short branch is 2:3.
[0059] Preferably, the width of the long branch node The range is 5.5mm to 6.5mm. The width of the short branch node... The range is 1.5mm to 2.5mm. Groove depth The range is from 3.5mm to 4.5mm.
[0060] More preferably, the width of the long branch node The width of the short branch High frequency and low frequency The mean parameters are -24.24dB and -22.08dB, respectively, and the mean axial ratio at low frequencies is 0.79dB.
[0061] More preferably, the groove depth Its high frequency The average parameter value is -17.97dB, and the average high-frequency axis ratio is 1.57dB.
[0062] Based on the above analysis, the structural dimensions of each part of the antenna are shown in Table 7 below.
[0063] Table 7 Antenna structural parameters
[0064] This invention discloses a novel dual-band dual-circular polarization satellite antenna that achieves dual-band dual-circular polarization by nesting an outer rectangular patch and an inner circular patch on the same plane, with perturbation and air layer co-optimization. By utilizing stub loading, slotted perturbation, and air layer to enhance gain and bandwidth, and employing a single-feed point circular polarization implementation, it achieves dual-band fusion and circular polarization performance, improved gain and anti-interference capabilities, and miniaturized and low-power design.
[0065] This embodiment presents a novel dual-frequency, dual-circularly polarized satellite antenna that simultaneously covers the L / C bands with a single structure. Employing a nested patch structure and a simple feeding method, it enhances signal stability in dynamic environments and simplifies satellite payload configuration. The antenna possesses multipath interference resistance, and its polarization characteristics reduce the impact of ionospheric scintillation on signals, ensuring the reliability of communication links.
[0066] Obviously, the above detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to describe preferred embodiments, not all embodiments, and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Based on the embodiments of the invention, any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art to all other embodiments obtained without inventive effort are within the scope of protection of the invention.
Claims
1. A novel dual frequency dual circular polarized satellite antenna characterized in that, The application relates to a single-feed-point coaxial line antenna, which comprises a ground plane, a single-feed-point coaxial line, a dielectric substrate and a metal patch connected to the dielectric substrate; a gap layer is arranged between the ground plane and the dielectric substrate; the single-feed-point coaxial line passes through the gap layer and the dielectric substrate to be electrically connected to the ground plane and the metal patch; the metal patch comprises an inner-layer circular patch and an outer-layer rectangular patch sleeved on the circular patch; the circular patch is provided with a rectangular slot to realize right-hand circular polarization; two pairs of edges of the rectangular patch are respectively provided with long branches and short branches to realize left-hand circular polarization; four corners or positions close to the four corners of the rectangular patch are electrically connected to the circular patch. The single-feed-point coaxial line is arranged on a diagonal line of the metal patch at a feeding position of the metal patch. The pair of edges of the rectangular patch provided with the short branches are electrically connected to the circular patch at positions close to the four corners of the rectangular patch.
2. A novel dual-frequency dual-circular polarized satellite antenna according to claim 1, characterized in that, The gap layer is an air layer. Feeding position of a single-feed point coaxial line in the range of 17.5 mm to 18.5 mm.
3. A novel dual-frequency dual-circular polarized satellite antenna according to claim 1, characterized in that, 4. A novel dual-frequency dual-circular polarized satellite antenna according to claim 1, characterized in that, The long branch is square in shape; the ratio of the width and length of the long branch is 1:1; The short branch node is rectangular in shape; the ratio of the width and length of the short branch node is 2:
3. The rectangular groove has a shape of a rectangle; a ratio of a width and a length of the rectangular groove is 4:
5.
5. A novel dual-frequency dual-circular polarized satellite antenna according to claim 1, characterized in that, the width of the long branch is in the range of 5.5 mm to 6.5 mm; the width of the short branch is in the range of 1.5 mm to 2.5 mm; The groove depth of the rectangular slot The range is from 3.5mm to 4.5mm.
6. A novel dual-frequency dual-circular polarized satellite antenna according to claim 1, characterized in that, 7. A novel dual-frequency dual-circular polarized satellite antenna according to claim 1, characterized in that, The thickness of the gap layer is in the range of 0.5 mm to 1.5 mm.
8. A novel dual-frequency dual-circular polarized satellite antenna according to claim 2, characterized in that, The feeding position ; width of the connection of the rectangular patch and the circular patch ; thickness of the gap layer .
9. A novel dual-frequency dual-circular polarized satellite antenna according to any one of claims 1 to 8, characterized in that, The rectangular patch is configured as a rectangular frame structure; the width of the frame ; width of the long branch length of the long branch width of the short branch length of the short branch .
10. A novel dual-frequency dual-circular polarized satellite antenna according to any one of claims 1 to 8, characterized in that, The width of the dielectric substrate was 120 mm, the length was 120 mm, and the thickness was 1.6 mm; the material of the dielectric substrate was FR4, the dielectric constant was 4.4, and the loss tangent angle was 0.0015.