Antenna and electronic device

Abstract

This utility model relates to the field of antenna structure technology, and discloses an antenna and electronic device. The antenna includes: a substrate on which a first antenna element and a second antenna element are disposed, both of which are dual-band antennas; a neutralization line connecting the first and second antenna elements to improve the isolation between them in a first operating frequency band; and a band-stop structure integrated on the substrate and disposed between the first and second antenna elements to improve the isolation between them in a second operating frequency band, which is higher than the first operating frequency band. In this utility model, by combining two different decoupling technologies—a neutralization line and a band-stop structure—each responsible for one frequency band, a dual-band high isolation performance is ultimately achieved on a single antenna.

Description

Technical Field

[0001] This utility model relates to the field of antenna structure technology, and in particular to antennas and electronic equipment. Background Technology

[0002] With the rapid development of the Internet of Things (IoT) technology, more and more electronic devices need to integrate antennas. In some applications, due to limitations in product size and functional requirements, multiple antennas operating in the same frequency band need to be placed within a very compact space. However, as the physical distance between antennas decreases, the electromagnetic coupling between them increases significantly. Electromagnetic coupling negatively impacts antenna performance, leading to a decline in communication quality.

[0003] Wi-Fi technology has become deeply integrated into modern life, and dual-band Wi-Fi has become the mainstream standard due to its advantages such as fast transmission speed, strong anti-interference ability, and flexible signal coverage. Users can choose different frequency bands according to their distance from the router to obtain the best network experience.

[0004] Conventional Wi-Fi antennas, due to their close physical proximity, experience severe coupling effects, resulting in generally poor isolation between them. This makes it difficult to meet performance targets greater than 14dB, ultimately degrading the overall communication performance of the antennas. Furthermore, some classic decoupling techniques require significant physical space to implement, making them unsuitable for compact spaces. Utility Model Content

[0005] The purpose of this invention is to provide an antenna and electronic device that can achieve high efficiency and high isolation of both Wi-Fi 2.4GHz and 5GHz dual-band signals within a relatively small size constraint.

[0006] To solve the above-mentioned technical problems, an embodiment of this utility model provides an antenna, comprising: A substrate, wherein a first antenna unit and a second antenna unit are disposed on the substrate, and both the first antenna unit and the second antenna unit are dual-band antennas; A neutral line connects the first antenna unit and the second antenna unit to improve the isolation between the first antenna unit and the second antenna unit in the first operating frequency band; A band-stop structure is integrated on the substrate and disposed between the first antenna unit and the second antenna unit to improve the isolation between the first antenna unit and the second antenna unit in a second operating frequency band, which is higher than the first operating frequency band.

[0007] In small-sized antennas, using only neutral lines or only band-stop structures for decoupling only achieves optimal results within a narrow frequency band, making it difficult to simultaneously cover two different frequency bands: the first and second operating frequency bands. This invention, compared to existing technologies, combines two different decoupling techniques—neutral lines and band-stop structures—each responsible for a specific frequency band, ultimately achieving high isolation across both frequency bands on a single antenna.

[0008] In addition, the band-resistance structure includes a defect grounding structure and an electromagnetic bandgap structure. The defect grounding structure is disposed on the grounding surface of the substrate, and the electromagnetic bandgap structure is disposed on the signal layer of the substrate.

[0009] Additionally, the defective grounding structure includes at least one slot etched onto the grounding surface of the substrate to extend the surface coupling current travel path between antenna elements. By etching slots corresponding to the decoupling frequency band onto the grounding surface, surface currents are coupled onto the slots, reducing mutual coupling between antenna elements.

[0010] Furthermore, the electromagnetic bandgap structure includes multiple periodically arranged metal patches to form a high-impedance surface in the second operating frequency band to suppress surface wave propagation. The metal patches and their underlying ground plane generate capacitive and inductive effects, forming an LC resonant network. By designing the size and spacing of the metal patches, the electromagnetic bandgap structure can exhibit extremely high surface impedance in the second operating frequency band. When a high-frequency coupled wave attempts to propagate between the first and second antenna elements, it encounters this high-impedance barrier, and its energy is reflected or suppressed, preventing further propagation and thus achieving efficient isolation.

[0011] Furthermore, the defect grounding structure and the electromagnetic bandgap structure at least partially overlap in projection position on the substrate. Both DGS and EBG are designed to suppress surface wave coupling occurring in this region. Aligning or overlapping the DGS at the bottom layer and the EBG at the top layer in projection means that these two structures act on the same physical region, enhancing the synergistic decoupling effect of DGS and EBG, thus optimizing the performance of the bandgap structure within the limited substrate space.

[0012] In addition, the substrate is a single-layer printed circuit board, which reduces the manufacturing cost and production complexity of the antenna.

[0013] In addition, the first operating frequency band is 2.4GHz to 2.5GHz, and the second operating frequency band is 5.15GHz to 5.85GHz, which conforms to the mainstream IEEE 802.11 series of WiFi standards, making it directly applicable to various WiFi products such as routers, laptops, and IoT gateways.

[0014] In addition, the first antenna unit and the second antenna unit are symmetrically arranged about the center line extending along the width direction of the substrate, which ensures that the electromagnetic environment of the two antenna units and their surroundings is highly similar, thus ensuring the consistency and balance of the performance of the two antenna channels.

[0015] In addition, both the first antenna unit and the second antenna unit are fed by coaxial cables. By laying coaxial cables, the antennas can be placed in the electronic equipment at the position with the best signal radiation and the least interference, thereby optimizing the overall performance of the device.

[0016] This application also provides an electronic device, including a housing and an antenna as described above, wherein the antenna is disposed within the housing. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a schematic diagram of the antenna structure provided in an embodiment of this application; Figure 2 yes Figure 1 The simulation and measured results of the antenna's VSWR (voltage standing wave ratio) are shown in the figure. Figure 3 yes Figure 1 The simulation and measured results of the antenna's scattering parameter curves are shown in the figure. Figure 4 yes Figure 1 The diagram shows the simulation and measured results of the antenna efficiency.

[0019] 10. Substrate; 11. First antenna element; 12. Second antenna element; 20. Neutral Line; 30. Resistance structure; 31. Defect grounding structure; 32. Electromagnetic bandgap structure. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this utility model to facilitate a better understanding of this application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0021] In this embodiment of the invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0022] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

[0023] Furthermore, the terms "installation," "setting," "equipped with," "opening," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0024] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0025] This application provides an antenna comprising a substrate 10, a first antenna element 11, a second antenna element 12, a neutralization line 20, and a band-stop structure 30. Both the first antenna element 11 and the second antenna element 12 are dual-band antennas and are both disposed on the substrate 10. The neutralization line 20 connects the first antenna element 11 and the second antenna element 12 to improve the isolation between the first antenna element 11 and the second antenna element 12 in a first operating frequency band. The band-stop structure 30 is integrated on the substrate 10 and disposed between the first antenna element 11 and the second antenna element 12 to improve the isolation between the first antenna element 11 and the second antenna element 12 in a second operating frequency band.

[0026] The antenna provided in this application embodiment is strictly limited in size to within 45mm × 30mm. See also... Figure 1The neutralization line 20 is shaped like a "Z", with one end connected to the first antenna element 11 and the other end connected to the second antenna element 12. Optionally, the neutralization line 20 is symmetrically arranged about the center line extending along the width direction of the substrate 10.

[0027] Neutralization line 20 is used to improve the isolation of the first operating frequency band. When the first antenna element 11 is operating, some energy is coupled to the second antenna element 12 via surface waves, forming a coupling path. Neutralization line 20, acting as a metallic connection between the first and second antenna elements 11, picks up a portion of the current from the first antenna element 11 and guides it to the second antenna element 12. By designing the length and connection position of neutralization line 20, the current phase on neutralization line 20 can be made approximately opposite to the current phase of the original coupling path. In this way, the radiation fields generated by the two paths cancel each other out in space, significantly reducing the mutual coupling between the antennas and improving the isolation of the first operating frequency band. Moreover, since the first operating frequency band is lower than the second operating frequency band, the narrow-band high-efficiency characteristic of neutralization line 20 is utilized to solve the coupling problem in the low-frequency band.

[0028] The band-stop structure 30 is disposed between the first antenna element 11 and the second antenna element 12 to form high impedance or block surface wave propagation in the second operating frequency band, thereby improving the isolation of the higher frequency band of the second operating frequency band.

[0029] The mutual coupling between the first antenna element 11 and the second antenna element 12 exhibits different characteristics in different frequency bands. In small-sized antennas, if only the neutralizing line 20 or only the band-stop structure 30 is used for decoupling, the best effect can only be achieved within a relatively narrow frequency band, making it difficult to simultaneously cover two different frequency bands, the first and second operating frequency bands. The antenna provided in this application combines two different decoupling techniques, the neutralizing line 20 and the band-stop structure 30, each responsible for one frequency band, ultimately achieving high isolation performance across two frequency bands on a single antenna.

[0030] In some specific embodiments of this application, the band-stop structure 30 includes a defective ground structure 31 and an electromagnetic band-gap structure 32. The defective ground structure 31 (DGS) is disposed on the ground surface of the substrate 10, and the electromagnetic band-gap structure 32 (EBG) is disposed on the signal layer of the substrate 10.

[0031] With only a single layer of DGS or EBG, the suppression capability of surface waves is limited. The defect grounding structure 31 is set on the grounding surface of the substrate 10, changing the current path of the ground plane and hindering coupling from the bottom layer; the electromagnetic bandgap structure 32 is set on the signal layer of the substrate 10, forming a high-impedance surface through resonance with the ground below, blocking the propagation of surface waves from the top layer. Through the synergistic effect of the upper and lower layers, a three-dimensional and more efficient band-stop filter is constructed, so that when high-frequency surface waves propagate between antennas, they are simultaneously suppressed by the top and bottom layers. Its suppression effect is far superior to any single structure, thus achieving stronger surface wave suppression capability and higher isolation in the second operating frequency band.

[0032] The defective grounding structure 31 includes at least one slot etched on the grounding surface of the substrate 10 to extend the travel path of surface coupling current between antenna elements.

[0033] In some optional embodiments, the defective grounding structure 31 includes a slot, and by etching a slot corresponding to the decoupling frequency band on the grounding surface, surface current is coupled onto the slot, reducing mutual coupling between antenna elements. In still other optional embodiments, the defective grounding structure 31 includes multiple slots, and by etching multiple slots, the current coupling path is extended to achieve the decoupling effect. See also Figure 1 The defective structure includes three vertical branches and one horizontal branch. The ends of the three vertical branches in the same direction are connected to the horizontal branch, forming a mountain-shaped structure. The middle vertical branch is located on the center line of the long side of the substrate 10, and the spacing between the two vertical branches on either side and the middle vertical branch is the same. "Vertical" refers to the width direction of the substrate 10, and "horizontal" refers to the length direction of the substrate 10. The horizontal extension direction is the same as the arrangement direction of the first antenna element 11 and the second antenna element 12.

[0034] The surface-coupled current between the first antenna element 11 and the second antenna element 12 tends to propagate along the shortest path. Etching slots on the ground plane is equivalent to setting up an obstacle in the current's inevitable path, forcing the coupled current to travel around the edge of the slots, thus changing the current distribution on the ground plane and extending the effective path of the coupled current. According to electromagnetic wave propagation theory, the signal transmission loss increases as the path lengthens. For high-frequency signals, the extended path leads to greater loss and phase change, effectively weakening the coupling strength. Therefore, when the coupled current reaches the adjacent antenna, its energy has been significantly weakened, thereby achieving the goal of reducing coupling and improving isolation.

[0035] The embodiments of this application effectively attenuate the intensity of coupling current by etching gap grooves, thereby contributing to improving the isolation in the high-frequency band.

[0036] The electromagnetic bandgap structure 32 includes multiple periodically arranged metal patches to form a high-impedance surface in the second operating frequency band to suppress surface wave propagation.

[0037] like Figure 1 As shown, the metal patch includes square patches and strip patches, wherein two square patches are symmetrically distributed along the width direction of the substrate 10. Multiple strip patches are also symmetrically distributed along the width direction of the substrate 10. Strip patches are evenly distributed above and below each square patch. (See reference...) Figure 1 Above the square patch, there is a strip-shaped patch extending along the length of the substrate 10, and below the square patch, there are three strip-shaped patches extending along the width of the substrate 10. The metal patches are connected to the defect grounding structure 31 via connecting vias. In addition, the metal patches can also take other shapes. For example, but not limited to, they can be circular, hexagonal, rectangular, cross-shaped, etc. These shapes are chosen to adjust the equivalent capacitance and / or inductance of the antenna element to optimize its surface wave suppression capability in the second operating frequency band. The scope of protection of this application is not limited by the specific geometry of the metal patch; any structure that uses periodic metal patches in conjunction with a ground plane to form band-stop characteristics falls within the scope of this application.

[0038] The periodically arranged metal patches and their underlying ground plane generate capacitance and inductance effects, forming an LC resonant network. By designing the size and spacing of the metal patches, the electromagnetic bandgap structure 32 can exhibit extremely high surface impedance in the second operating frequency band. According to electromagnetic field theory, surface waves cannot propagate effectively on a surface with high impedance. Therefore, when a high-frequency coupled wave attempts to propagate from the first antenna element 11 to the second antenna element 12, or from the second antenna element 12 to the first antenna element 11, it encounters this high-impedance barrier, and its energy is reflected or suppressed, preventing further propagation, thus achieving efficient isolation.

[0039] The antenna provided in this application embodiment forms an electromagnetic barrier against high-frequency surface waves on the signal layer surface between the first antenna unit 11 and the second antenna unit 12 through periodically arranged metal patches, effectively preventing the propagation of coupled energy and improving the isolation of the high-frequency band.

[0040] The projection positions of the defect grounding structure 31 and the electromagnetic bandgap structure 32 on the substrate 10 at least partially overlap.

[0041] The region with the strongest coupling between the first antenna element 11 and the second antenna element 12 is precisely the space between them. Both DGS and EBG are designed to suppress surface wave coupling occurring in this region. Aligning or overlapping the DGS located at the bottom layer and the EBG located at the top layer in projection means that these two structures act on the same physical region, enhancing the synergistic decoupling effect of DGS and EBG, thereby optimizing the performance of the band-stop structure 30 within the limited space of the substrate 10.

[0042] Optionally, the substrate 10 is a single-layer printed circuit board (PCB).

[0043] The manufacturing process of multilayer PCBs involves complex steps such as laminating multiple layers, interlayer alignment, drilling, and electroplating, resulting in significantly higher costs than single-layer PCBs. Using a single-layer printed circuit board reduces antenna manufacturing costs and production complexity. Compared to the complex DGS or EBG structures that require multiple PCBs to achieve good broadband decoupling, this application achieves the goal using only a single-layer PCB. The entire fabrication process involves only standard PCB etching processes, requiring no additional manufacturing steps or special materials, thus resulting in extremely low manufacturing costs.

[0044] The antenna provided in this embodiment has an electromagnetic bandgap structure 32 disposed on the signal layer of a single-layer PCB, and a defect grounding structure 31 disposed on the grounding surface of the single-layer PCB, eliminating the need for an additional PCB layer. It can be manufactured using standard single-layer PCB processes, avoiding the high costs and lower production yield associated with multilayer boards.

[0045] Specifically, the first operating frequency band is 2.4GHz to 2.5GHz, and the second operating frequency band is 5.15GHz to 5.85GHz.

[0046] The antenna operates in two frequency bands: 2.4GHz-2.5GHz and 5.15GHz-5.85GHz, conforming to the mainstream IEEE 802.11 series of WiFi standards. By designing the neutralization line 20 in the 2.4GHz band and the band-stop structure 30 in the 5GHz band, the antenna provided in this application solves the antenna element isolation problem encountered during device miniaturization, allowing it to be directly applied to various WiFi products such as routers, laptops, and IoT gateways.

[0047] See Figure 1 The first antenna element 11 and the second antenna element 12 are symmetrically arranged about the center line extending along the width direction of the substrate 10.

[0048] In multiple-input multiple-output (MIMO) systems, significant differences in gain, radiation pattern, impedance, and other performance characteristics between two antenna channels can negatively impact data throughput and connection stability. The antenna provided in this embodiment achieves a physically symmetrical layout of the two antennas by symmetrically arranging the first antenna element 11 and the second antenna element 12. This ensures a high degree of similarity between the two antenna elements and their surrounding electromagnetic environment, guaranteeing the consistency and balance of the performance of the two antenna channels. Furthermore, the symmetrical arrangement of the first antenna element 11 and the second antenna element 12 theoretically makes the key performance indicators such as S-parameters and radiation patterns of the two antenna elements completely identical, simplifying the antenna design and simulation verification process.

[0049] Both the first antenna element 11 and the second antenna element 12 are fed by coaxial cables.

[0050] See Figure 1 The feed points of the first antenna element 11 and the second antenna element 12 are symmetrically arranged about the center line extending along the width direction of the substrate 10. Two coaxial cables are correspondingly soldered to the two feed points, making the assembly process simple and flexible. The coaxial cable consists of a central conductor and an outer shielding layer, which can effectively transmit the radio frequency signal from the motherboard to the antenna. At the same time, its shielding layer can prevent external electromagnetic noise from interfering with the signal and can also prevent the feed line itself from generating unnecessary radiation.

[0051] The motherboard and antenna of the electronic device are separated. A coaxial cable is laid between the motherboard and the first antenna unit 11 and the second antenna unit 12 to achieve power supply connection. Thus, by laying the coaxial cable, the antenna can be placed in the position of optimal signal radiation and minimal interference in the electronic device, thereby optimizing the overall performance.

[0052] The antenna provided in this application embodiment uses a coaxial cable to feed the first antenna element 11 and the second antenna element 12, providing a flexible, reliable connection method with good electromagnetic shielding, which facilitates product integration and protects the antenna performance from interference from other circuits inside the device.

[0053] In the prior art, the neutralization line 20, due to its narrowband characteristics, is difficult to simultaneously support dual frequencies; while single-layer DGS has poor high-frequency suppression performance. This application utilizes the synergistic effect of the neutralization line 20 and the band-stop structure 30 to effectively suppress the mutual coupling between the first antenna element 11 and the second antenna element 12, reducing energy leakage to below 1 / 25 (-14dB ≈ 1 / 25.1), so that the isolation between the first antenna element 11 and the second antenna element 12 is greater than 14dB within the operating frequency band.

[0054] Furthermore, the antenna's radiation efficiency = (total input power - loss power) / total input power. Coupling between antennas is a significant pathway for energy loss. The efficient decoupling achieved through the synergistic effect of the neutralization line 20 and the band-stop structure 30 significantly reduces coupling loss, allowing more energy to be effectively radiated and achieving high radiation efficiency. Specifically, the antenna provided in this embodiment exhibits a radiation efficiency greater than 65% in the 2.4GHz to 2.5GHz frequency band and greater than 45% in the 5.15GHz to 5.85GHz frequency band.

[0055] Therefore, this application utilizes the advantages of the 20-pair neutralization line for high efficiency in low-frequency narrowband applications, while simultaneously combining the DGS and EBG structures to form a high-frequency bandstop filter. The two technologies are structurally integrated in the same region, but functionally distinct, ultimately achieving efficient decoupling of two different frequency bands simultaneously within a single, simple structure.

[0056] refer to Figure 2 The horizontal axis represents frequency, and the vertical axis represents VSWR (Voltage Standing Wave Ratio). Simulation and measured VSWR results show that in both the 2.4-2.5 GHz and 5.15-5.85 GHz target frequency bands, the antenna's VSWR value is less than 2, indicating good matching between the antenna and the feeding system, and that energy can be effectively radiated. Figure 2 As can be seen, the antenna provided in this application embodiment has good impedance matching.

[0057] refer to Figure 3 The horizontal axis represents frequency, and the vertical axis represents the S12 parameters, i.e., the reverse transmission coefficient. Simulation and experimental results of the scattering parameter curves show that the reverse transmission coefficient between the two antenna elements is better than -14dB across the entire operating frequency band, and even reaches above -20dB at some frequency points. This fully demonstrates the low energy leakage during signal reverse transmission, thus proving the effectiveness of the composite decoupling structure. Figure 3 As can be seen, the antenna provided in this application embodiment has excellent isolation.

[0058] refer to Figure 4 Efficiency simulation and experimental results show that the average efficiency of the 2.4GHz band is higher than 65%, and the average efficiency of the 5GHz band is higher than 45%, meeting the requirements of high-performance Wi-Fi communication. Figure 4 As can be seen, the antenna provided in this application embodiment has high radiation performance.

[0059] This application also provides an electronic device, including a housing and an antenna as described above disposed within the housing.

[0060] The antenna provided by the embodiments of this utility model has been described in detail above. Specific examples have been used in this article to illustrate the principle and implementation of this utility model. The above description of the embodiments is only for the purpose of helping to understand the idea of ​​this utility model. There may be changes in the specific implementation and application scope. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An antenna, characterized in that, include: A substrate, wherein a first antenna unit and a second antenna unit are disposed on the substrate, and both the first antenna unit and the second antenna unit are dual-band antennas; A neutral line connects the first antenna unit and the second antenna unit to improve the isolation between the first antenna unit and the second antenna unit in the first operating frequency band; A band-stop structure is integrated on the substrate and disposed between the first antenna unit and the second antenna unit to improve the isolation between the first antenna unit and the second antenna unit in a second operating frequency band, which is higher than the first operating frequency band.

2. The antenna according to claim 1, characterized in that, The band-resistance structure includes a defect grounding structure and an electromagnetic bandgap structure. The defect grounding structure is disposed on the grounding surface of the substrate, and the electromagnetic bandgap structure is disposed on the signal layer of the substrate.

3. The antenna according to claim 2, characterized in that, The defective grounding structure includes at least one slot etched on the grounding surface of the substrate to extend the surface coupling current travel path between antenna elements.

4. The antenna according to claim 2, characterized in that, The electromagnetic bandgap structure includes multiple periodically arranged metal patches to form a high-impedance surface in the second operating frequency band to suppress surface wave propagation.

5. The antenna according to claim 2, characterized in that, The defect grounding structure and the electromagnetic bandgap structure at least partially overlap on the projection position of the electromagnetic bandgap structure on the substrate.

6. The antenna according to claim 1, characterized in that, The substrate is a single-layer printed circuit board.

7. The antenna according to claim 1, characterized in that, The first operating frequency band is 2.4 GHz to 2.5 GHz, and the second operating frequency band is 5.15 GHz to 5.85 GHz.

8. The antenna according to claim 1, characterized in that, The first antenna element and the second antenna element are symmetrically arranged about a centerline extending along the width direction of the substrate.

9. The antenna according to claim 1, characterized in that, Both the first antenna unit and the second antenna unit are fed via coaxial cables.

10. An electronic device, characterized in that, It includes a housing and an antenna as described in any one of claims 1 to 9, wherein the antenna is disposed within the housing.

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