A full-sky communication antenna applied to a vehicle-mounted communication system

Abstract

The application relates to a full-space communication antenna. The full-space communication antenna applied to a vehicle-mounted communication system comprises a satellite covering antenna, a ground covering antenna and a one-to-five feeding network; the satellite covering antenna is a circularly polarized directional antenna, and the ground covering antenna is a vertical polarization omnidirectional antenna; the satellite covering antenna is arranged directly above the ground covering antenna to ensure that the mutual influence between the two antennas is minimized; the one-to-five feeding network is located below the ground covering antenna to control the energy distribution and phase control between the two antennas. The combination of the circularly polarized satellite covering antenna and the vertical polarization ground covering antenna realizes the integration of antennas with different polarizations and different functions; the system complexity of the antenna is reduced, and the volume of the antenna is reduced by improving the antenna composition and the feeding mode; the vertical polarization omnidirectional gain is improved by using an array antenna as the ground covering antenna.

Description

Technical Field

[0001] This invention relates to an antenna technology, and more particularly to an all-space communication antenna for use in vehicle communication systems, which mainly solves the problem that existing all-space communication antennas cannot simultaneously achieve large size and high complexity while maintaining low elevation gain. Background Technology

[0002] An antenna is an electromagnetic energy converter that transforms electromagnetic waves radiated in free space into guided waves on a transmission line. In a wireless device, the antenna is typically positioned at the front end of the system, and its performance significantly impacts the overall performance of the radio system. Radio systems rely on antennas for operation, especially vehicle-mounted communication systems that incorporate broadcasting, radar, navigation, and other functions. With the development of vehicle-to-everything (V2X) technology, the functions of V2X communication systems are increasing, and the number of carriers requiring radio communication with vehicles is also growing. These carriers typically have different locations, frequency ranges, and polarizations. Full-space communication refers to continuous communication with multiple targets within the entire airspace (typically elevation 5°-90°, azimuth 0°-360°) that exhibit different trajectories, frequencies, polarizations, and signal formats.

[0003] The 27th Research Institute of China Electronics Technology Group Corporation disclosed a spherical phased array antenna in its patent application "A Vehicle-Mounted Spherical Phased Array Antenna" (application number CN202222982304.5, authorization announcement number CN 218351721 U). This antenna employs a hemispherical upper section, primarily responsible for receiving high-elevation satellite signals, with a height of 1 / 3 to 1 / 2 of the overall height. The lower section adopts a cylindrical layout, primarily responsible for receiving low-elevation satellite signals, improving beam gain at low elevation angles, with a height of 1 / 2 to 2 / 3 of the overall height. This allows for full airspace coverage, enabling tracking and reception of satellite signals across the entire airspace from azimuth 0° to 360° and elevation 0° to 90°. However, this antenna still has shortcomings, such as the large antenna size and system complexity resulting from using multiple antenna arrays.

[0004] Xi'an Aerospace Tianhui Data Technology Co., Ltd., in its patent application "A Broadband Thin-Film Phased Array Antenna" (application number CN 202311690983.1, publication number CN 117525828 A), provides a broadband thin-film phased array antenna. This antenna achieves full-space beam coverage by employing switched phased array and air-coupled antenna technologies, exhibiting a wide standing wave bandwidth and axial ratio bandwidth. Furthermore, its thin-film structure results in lightweight and compact design, allowing for efficient convergence and a larger radiating aperture. However, a remaining drawback is its low gain at low elevation angles, making it unsuitable for communication with targets at low elevation angles.

[0005] In summary, to achieve full-space coverage communication, existing technologies employ complex curved array and pattern integration designs, resulting in complex and bulky antenna structures. Others use low-profile array designs, but these often fail to meet the antenna gain requirements at low elevation angles. The problem of balancing antenna size and low-elevation-angle gain urgently needs to be solved. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by proposing an all-space communication antenna for use in vehicle communication systems. The aim is to reduce the system complexity and size of the all-space communication antenna while improving its gain at low elevation angles.

[0007] The technical solution adopted in this invention is as follows:

[0008] A full-space communication antenna for vehicle-mounted communication systems includes a satellite coverage antenna (1), a ground coverage antenna (2), and a 1-to-5 power divider network (3). The satellite coverage antenna (1) is a circularly polarized directional antenna; the ground coverage antenna (2) is a vertically polarized omnidirectional antenna; the satellite coverage antenna (1) is positioned directly above the ground coverage antenna (2); the phase difference between the satellite coverage antenna (1) and the ground coverage antenna (2) is P, the power distribution ratio is A:4, and both P and A vary with frequency; the 1-to-5 power divider network (3) is located below the ground coverage antenna (2) and is an air-based power divider network.

[0009] The one-to-five power distribution network (3) is an unequal power distribution network. Among the five output ports of the one-to-five power distribution network (3), ports 1, 2, 4 and 5 have the same power distribution. Port 3 has a different power distribution from the other four ports. The power distribution ratio of port 3 to the other ports is A:4. The phase difference between port 3 and the other ports is P.

[0010] The one-to-five power supply network (3) adopts an air-line form, the thickness of the power supply network line (303) is T1, and the thickness of the air between the power supply network and the ground is T2.

[0011] The 1-to-5 power distribution network (3) consists of two power distribution networks. The first power distribution network is a 1-to-3 power distribution network, and the second power distribution network is a 1-to-2 power distribution network. The second power distribution network is only set on two of the three output ports of the first power distribution network, forming a 1-to-5 power distribution network.

[0012] The satellite coverage antenna (1) is located directly above the ground coverage antenna (2), and the distance between the satellite coverage antenna (1) and the ground coverage antenna (2) is H1.

[0013] The satellite-targeting coverage antenna (1) includes a satellite-targeting radome (101), a satellite-targeting radiator (102), and a satellite-targeting feed network (103). The satellite-targeting radiator (102) consists of two orthogonally placed magnetoelectric dipoles, which are fed by signals from the satellite-targeting feed network (103) to achieve circular polarization. The satellite-targeting feed network (103) is located on the back of the satellite-targeting radiator (102).

[0014] The ground-covering antenna (2) includes a ground-covering radome (201), a ground-covering radiator (202), a ground-covering passive stub (203), and a ground-covering support structure (204). The ground-covering radiator (202) consists of four pairs of identical metal biconical antennas, each pair of biconical antennas being divided into an upper radiating arm and a lower radiating arm. The lower radiating arm is fixed to the ground-covering support structure (204), and the upper radiating arm is fixed to the lower radiating arm. The ground-covering passive stub (203) consists of four bowl-shaped structures, each bowl-shaped structure being positioned directly above the upper radiating arm of the corresponding ground-covering radiator (202). Both the ground-covering radiator (202) and the ground-covering passive stub (203) are fixed to the ground-covering support structure (204). The radiating arm is passed through the middle by the ground-covering support structure (204).

[0015] The 1-to-5 power supply network (3) includes a support base (301), a power supply network cavity (302), a power supply network cable (303), and a power supply network cover plate (304). The support base (301) is a cylindrical metal structure, and the power supply network cavity (302), the power supply network cable (303), and the power supply network cover plate (304) are all located inside it. The power supply network cavity (302) is fixed to the bottom of the support base (301) to provide an installation position and cable environment for the power supply network cable (303). The power supply network cable (303) is located between the power supply network cavity (302) and the power supply network cover plate (304).

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] First, the present invention applies to the all-space communication antenna of the vehicle communication system. By adopting a combination of a circularly polarized satellite coverage antenna and a vertically polarized ground coverage antenna, the integration of antennas with different polarizations and functions is realized, which can simultaneously achieve satellite coverage communication and ground coverage communication, thus achieving all-space coverage communication.

[0018] Secondly, this invention uses a combination of satellite coverage antenna and ground coverage antenna instead of the traditional combination of hemispherical array and cylindrical array for all-space antennas, and uses a single-network feeding method instead of the back-end active T / R feeding method, which greatly reduces the system complexity of the antenna and reduces the size of the antenna.

[0019] Third, this invention uses a four-element linear array antenna as the ground coverage antenna and a biconical antenna as the antenna element of the array antenna, so that the ground coverage antenna has a good omnidirectional radiation pattern in the operating frequency range and the all-space communication antenna has a high low elevation angle gain in the operating frequency range.

[0020] Simulation results show that the present invention has good left-hand circular polarization orientation pattern and vertical polarization omnidirectional pattern, impedance matching relative bandwidth of about 60% with voltage standing wave ratio less than 2, and azimuth vertical polarization non-circularity of less than 2.88dB throughout the entire frequency band. Attached Figure Description

[0021] Figure 1 This is an overall structural diagram of the present invention;

[0022] Figure 2 This is an exploded view of the satellite coverage antenna of the present invention;

[0023] Figure 3 This is an exploded view of the ground coverage antenna of the present invention;

[0024] Figure 4 This is an exploded view of the one-to-five power distribution network of the present invention;

[0025] Figure 5 This is a simulation result diagram of the voltage standing wave ratio of the present invention;

[0026] Figure 6 This is a simulation result of the azimuth plane vertical polarization normalized radiation pattern of the present invention;

[0027] Figure 7 This is a simulation result of the variation of the azimuth plane vertical polarization non-circularity with frequency according to the present invention;

[0028] Figure 8 This is a simulation result of the normalized radiation pattern of the left-hand circular polarization on the elevation plane according to the present invention; Detailed Implementation

[0029] To make the technical concept and advantages of the invention clearer, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are only used to explain and illustrate preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0030] Example 1

[0031] Reference Figure 1The all-space communication antenna for a vehicle-mounted communication system described in this invention consists of a satellite coverage antenna 1, a ground coverage antenna 2, and a 1-to-5 feed network 3. The satellite coverage antenna 1 is positioned directly above the ground coverage antenna 2 to minimize mutual interference between the two antennas; the 1-to-5 feed network 3 is located at the bottom and controls the energy distribution and phase control between the two antennas.

[0032] Reference Figure 2 The satellite-monitoring antenna 1 consists of a satellite-monitoring radome 101, a satellite-monitoring radiator 102, and a satellite-monitoring feed network 103. The satellite-monitoring radome 101 is made of fiberglass and has a bowl-shaped structure. The satellite-monitoring radiator 102 consists of two orthogonally placed magnetoelectric dipoles. The signal from the satellite-monitoring feed network 103 feeds the two magnetoelectric dipoles, enabling them to achieve circular polarization. The ends of the electric dipoles are bent downwards to extend the beamwidth. Four structural components surround the magnetoelectric dipoles for fixation, ensuring strong vibration resistance. The satellite-monitoring feed network 103 is an air-wire network, 1 mm thick, installed in a cavity on the back of the antenna floor. The satellite-monitoring feed network 103 consists of a power divider network and a phase-shifting network, with one input port and two output ports. By feeding the input port, the satellite-monitoring feed network 103 can convert one signal into two signals with the same power but a 90° phase difference.

[0033] Reference Figure 3 The ground-covering antenna 2 consists of a ground-covering radome 201, a ground-covering radiator 202, a ground-covering passive stub 203, and a ground-covering support structure 204. The ground-covering radome 201 is made of fiberglass and has a cylindrical structure. The ground-covering radiator 202 consists of four pairs of identical metal biconical antennas, each pair divided into an upper radiating arm and a lower radiating arm. The lower radiating arm is fixed to the ground-covering support structure 204, and the upper radiating arm is fixed to the lower radiating arm, with the ground-covering support structure 204 passing through the middle of the radiating arms. Numerous weight-reducing holes are provided on the radiating arms. The ground-covering passive stub 203 consists of four bowl-shaped structures, each positioned directly above the corresponding upper radiating arm. All ground-covering passive stubs 203 are fixed to the ground-covering support structure 204. Numerous weight-reducing holes are provided on the ground-covering passive stub 203.

[0034] Reference Figure 4The 1-to-5 power divider network 3 consists of a support base 301, a power divider cavity 302, a power divider cable 303, and a power divider cover plate 304. The support base 301 is a cylindrical metal structure, housing the power divider cavity 302, the power divider cable 303, and the power divider cover plate 304. The power divider cavity 302 is fixed to the bottom of the support base 301, providing an installation position and environment for the power divider cable 303. The power divider cable 303 is an air-supported cable network, 1mm thick. It consists of multiple power dividers, with one input port and five output ports. Four of the output ports have equal amplitude and phase, while the remaining port has different amplitudes and phases. The power divider cover plate 304 is a flat metal plate, primarily used to create the cable environment with the power divider cavity 302, ensuring the normal operation of the power divider network.

[0035] The effectiveness of this example can be further illustrated by the following simulation experiments:

[0036] Using High Frequency Structure Simulator simulation software, such as Figure 1 The model shown was simulated, and the results were as follows: Figures 5 to 7 The simulation results are shown.

[0037] Figure 5 This is a simulation result diagram of the voltage standing wave ratio of the present invention. Figure 5 The horizontal axis represents frequency, and the vertical axis represents the voltage standing wave ratio (VSWR) of the antenna feed port of this invention. Figure 5 The curve in the figure represents the voltage standing wave ratio (VSWR) of the antenna feed port of the present invention as a function of frequency from 0.7 GHz to 1.3 GHz. As can be seen from the figure, the voltage standing wave ratio of the antenna of the present invention is less than 2 in the range of 0.7 GHz to 1.3 GHz. At the center frequency of 1.0 GHz, the impedance matching bandwidth is calculated to be the percentage of the bandwidth (1.3-0.7) GHz to the center frequency of 1.0 GHz. The relative impedance matching bandwidth with a voltage standing wave ratio of less than 2 is approximately 60%.

[0038] Figure 6 The figure shows the simulation results of the azimuth plane vertical polarization normalized radiation pattern of the present invention. As can be seen from the figure, the vertical polarization antenna pattern of the present invention has good omnidirectional performance in the azimuth plane, which can meet the requirements of ground coverage.

[0039] Figure 7 This is a simulation result of the variation of the azimuth plane vertical polarization non-circularity with frequency according to the present invention. Figure 7 The horizontal axis represents frequency, and the vertical axis represents the azimuth plane vertical polarization non-circularity of this invention. Figure 7The curve in the figure represents the variation of the azimuth plane vertical polarization non-circularity of the present invention with frequency from 0.7 GHz to 1.3 GHz. As can be seen from the figure, the azimuth plane vertical polarization non-circularity of the present invention is less than 2.88 dB between 0.7 GHz and 1.3 GHz.

[0040] Figure 8 The figure shows the simulation results of the normalized radiation pattern of the left-hand circularly polarized antenna in the elevation plane of the present invention. As can be seen from the figure, the left-hand circularly polarized antenna pattern of the present invention has good radiation performance in the elevation plane, which can meet the requirements of satellite coverage.

[0041] Example 2

[0042] See Figure 1 This invention relates to an all-space communication antenna for a vehicle-mounted communication system, comprising a satellite coverage antenna 1, a ground coverage antenna 2, and a 1-to-5 power divider network 3. The satellite coverage antenna 1 is a circularly polarized directional antenna; the ground coverage antenna 2 is a vertically polarized omnidirectional antenna. The satellite coverage antenna 1 is positioned directly above the ground coverage antenna 2 to minimize mutual interference between the two antennas. The 1-to-5 power divider network 3 is located below the ground coverage antenna 2 and is an air-line power divider network to control energy distribution and phase control between the two antennas. The phase difference between the satellite coverage antenna 1 and the ground coverage antenna 2 is P, and the power distribution ratio is A:4, with both P and A varying with frequency.

[0043] Among them, the ground coverage antenna 2 is a four-element array antenna, with each antenna element having the same feed phase and feed power. The feed power of the satellite coverage antenna 1 and the ground coverage antenna 2 is normalized to the feed power of each antenna element, resulting in a normalized feed power of A for the satellite coverage antenna 1 and a normalized feed power of 4 for the ground coverage antenna 2. The feed phase of the satellite coverage antenna 1 and the ground coverage antenna 2 is normalized to the feed phase of each antenna element, resulting in a normalized feed phase of P for the satellite coverage antenna 1 and a normalized feed phase of 0 for the ground coverage antenna 2.

[0044] Example 3

[0045] The all-space communication antenna applied to the vehicle communication system in this embodiment differs from that in Embodiment 2 in that: the 1-to-5 feeder network 3 is an unequal power distribution network. Among the five output ports of the 1-to-5 feeder network 3, ports 1, 2, 4, and 5 have the same power allocation, while port 3 has a different power allocation from the other four ports. The power allocation ratio between port 3 and the other ports is A:4, and the phase difference between port 3 and the other ports is P.

[0046] Example 4

[0047] The all-space communication antenna applied to the vehicle communication system in this embodiment differs from those in embodiments 2 or 3 in that: further, see... Figure 2 The satellite-targeting coverage antenna 1 includes a satellite-targeting radome 101, a satellite-targeting radiator 102, and a satellite-targeting feed network 103. The satellite-targeting radiator 102 consists of two orthogonally placed magnetoelectric dipoles, which are fed by signals from the satellite-targeting feed network 103 to achieve circular polarization. The satellite-targeting feed network 103 is located on the back side of the satellite-targeting radiator 102.

[0048] In particular, bending the ends of the electric dipoles in the star radiator 102 downwards can achieve the effect of expanding the beamwidth.

[0049] The satellite feed network 103 consists of a power divider network and a phase shifter network, with one input port and two output ports. By feeding the input port, the satellite feed network 103 converts one signal into two signals with the same power but a 90° phase difference.

[0050] Example 5

[0051] This embodiment is applied to the all-space communication antenna of the vehicle communication system. The difference from the previous embodiments is that the 1-to-5 feed network 3 is an unequal power feed network that simultaneously feeds the satellite coverage antenna 1 and the ground coverage antenna 2.

[0052] The ground coverage antenna 2 is a four-element array antenna, in which two adjacent antenna elements have an orientation angle difference of 90° around the antenna axis.

[0053] Example 6

[0054] The all-space communication antenna for vehicle-mounted communication systems in this embodiment differs from that in Embodiment 5 in that: the ground-covering antenna 2 includes a ground-covering radome 201, a ground-covering radiator 202, a ground-covering passive stub 203, and a ground-covering support structure 204; the ground-covering radiator 202 consists of four pairs of identical metal biconical antennas, each pair being divided into an upper radiating arm and a lower radiating arm; the lower radiating arm is fixed to the ground-covering support structure 204, and the upper radiating arm is fixed to the lower radiating arm; the ground-covering passive stub 203 consists of four bowl-shaped structures, each bowl-shaped structure being positioned directly above the upper radiating arm of the corresponding ground-covering radiator 202; both the ground-covering radiator 202 and the ground-covering passive stub 203 are fixed to the ground-covering support structure 204; the radiating arm is passed through the middle by the ground-covering support structure 204. The ground-covering passive stub 203 is located above the ground-covering radiator 202.

[0055] Example 7

[0056] The all-space communication antenna applied to the vehicle-mounted communication system in this embodiment differs from the aforementioned embodiments in that: the 1-to-5 feed network 3 further includes a support base 301, a feed network cavity 302, a feed network cable 303, and a feed network cover plate 304; the support base 301 is a cylindrical metal structure, and the feed network cavity 302, the feed network cable 303, and the feed network cover plate 304 are all disposed inside it; the feed network cavity 302 is fixed to the bottom of the support base 301, providing an installation position and cable environment for the feed network cable 303; the feed network cable 303 is located between the feed network cavity 302 and the feed network cover plate 304; the 1-to-5 feed network 3 is an unequal power distribution feed network, simultaneously feeding both the satellite coverage antenna 1 and the ground coverage antenna 2.

[0057] Example 8

[0058] The all-space communication antenna applied to the vehicle communication system in this embodiment differs from that in Embodiment 7 in that: the 1-to-5 power divider network 3 and the satellite-following power divider network 103 are both air-line power dividers; the satellite-following power divider network 103 is installed in the cavity behind the floor of the satellite-following coverage antenna 1; the power divider network line 303 consists of a multi-stage power divider with one input port and five output ports, of which four output ports have the characteristics of equal amplitude and in-phase, and the other port has different amplitude and phase; the power divider network cover plate 304 is a metal plate, mainly used to form a line environment with the power divider network cavity 302 to enable the power divider network to work normally.

[0059] The present invention relates to an all-space communication antenna for a vehicle-mounted communication system, wherein the ground radiator 202 and the ground passive stub 203 are provided with weight reduction holes to reduce the weight of the antenna.

[0060] This invention integrates antennas with different polarizations and functions by combining a circularly polarized satellite coverage antenna 1 with a vertically polarized ground coverage antenna 2; it broadens the operating bandwidth of the antenna through a multi-stage feeding network; and it improves the omnidirectional gain of vertical polarization by using an array antenna as the ground coverage antenna 2.

[0061] The above description is merely a preferred embodiment of the present invention and does not constitute a limitation thereof. Those skilled in the art, guided by existing technology, can make other modifications to the implementation of the present invention without creative effort. Any modifications made within the spirit and principles of the present invention, or simple substitutions or equivalent replacements using conventional techniques in the art, should be included within the scope of protection of the present invention.

Claims

1. A full-space communication antenna for use in a vehicle-mounted communication system, comprising a satellite coverage antenna (1), a ground coverage antenna (2), and a 1-to-5 feed network (3), characterized in that: The satellite coverage antenna (1) is a circularly polarized directional antenna; the ground coverage antenna (2) is a vertically polarized omnidirectional antenna; the satellite coverage antenna (1) is positioned directly above the ground coverage antenna (2); the phase difference between the satellite coverage antenna (1) and the ground coverage antenna (2) is P, the power distribution ratio is A:4, and both P and A vary with frequency; the 1-to-5 power divider network (3) is located below the ground coverage antenna (2) and is an air-line power divider network; The satellite-targeting coverage antenna (1) includes a satellite-targeting radome (101), a satellite-targeting radiator (102), and a satellite-targeting feed network (103); the satellite-targeting radiator (102) consists of two orthogonally placed magnetoelectric dipoles, which are fed by signals from the satellite-targeting feed network (103) to achieve circular polarization; the satellite-targeting feed network (103) is located on the back of the satellite-targeting radiator (102); The ground-covering antenna (2) includes a ground-covering radome (201), a ground-covering radiator (202), a ground-covering passive stub (203), and a ground-covering support structure (204). The ground-covering radiator (202) consists of four pairs of identical metal biconical antennas, each pair of biconical antennas being divided into an upper radiating arm and a lower radiating arm. The lower radiating arm is fixed on the ground-covering support structure (204), and the upper radiating arm is fixed on the lower radiating arm. The ground-covering passive stub (203) consists of four bowl-shaped structures, each bowl-shaped structure being positioned directly above the upper radiating arm of the corresponding ground-covering radiator (202). The ground-covering radiator (202) and the ground-covering passive stub (203) are both fixed on the ground-covering support structure (204). The radiating arm is passed through the middle by the ground-covering support structure (204).

2. The all-space communication antenna for a vehicle-mounted communication system according to claim 1, characterized in that: The one-to-five power distribution network (3) is an unequal power distribution network. Among the five output ports of the one-to-five power distribution network (3), ports 1, 2, 4 and 5 have the same power distribution. Port 3 has a different power distribution from the other four ports. The power distribution ratio of port 3 to the other ports is A:

4. The phase difference between port 3 and the other ports is P.

3. The all-space communication antenna for a vehicle-mounted communication system according to claim 1, characterized in that: The one-to-five power supply network (3) adopts an air-line form, the thickness of the power supply network line (303) is T1, and the thickness of the air between the power supply network and the ground is T2.

4. The all-space communication antenna for a vehicle-mounted communication system according to claim 1, characterized in that: The 1-to-5 power distribution network (3) consists of two power distribution networks. The first power distribution network is a 1-to-3 power distribution network, and the second power distribution network is a 1-to-2 power distribution network. The second power distribution network is only set on two of the three output ports of the first power distribution network, forming a 1-to-5 power distribution network.

5. The all-space communication antenna for a vehicle-mounted communication system according to claim 1, characterized in that: The satellite coverage antenna (1) is located directly above the ground coverage antenna (2), and the distance between the satellite coverage antenna (1) and the ground coverage antenna (2) is H1.

6. The all-space communication antenna for a vehicle-mounted communication system according to claim 1, characterized in that: The 1-to-5 power supply network (3) includes a support base (301), a power supply network cavity (302), a power supply network cable (303), and a power supply network cover plate (304). The support base (301) is a cylindrical metal structure, and the power supply network cavity (302), the power supply network cable (303), and the power supply network cover plate (304) are all located inside it. The power supply network cavity (302) is fixed to the bottom of the support base (301) to provide an installation position and cable environment for the power supply network cable (303). The power supply network cable (303) is located between the power supply network cavity (302) and the power supply network cover plate (304).

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