Method and signal filter unit for controlling energy loss in a wireless device in a wireless network

Abstract

Embodiments of present disclosure provide signal filter unit (200) and method (500) for controlling energy loss during operation of wireless device in wireless network (106). The method (500) fabricates the signal filter unit (200) by fabricating filter layer (202) having filter (204). The filter (204) has cavity (206) and resonator (208) arranged in cavity (206). Further, the method (500) fabricates two secondary layers (210) having predefined cavity (212). Thereafter, the method (500) arranges two secondary layers (210) to enclose filter layer (202). The predefined cavity (212) of two secondary layers (210) is cylindrical and is coaxial with cavity (206) of filter (204) of the filter layer (202).

Description

[0001] METHOD AND SIGNAL FILTER UNIT FOR CONTROLLING ENERGY LOSS IN A WIRELESS DEVICE IN A WIRELESS NETWORK

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to a field of signal filters. More particularly, it relates to the signal filters in a wireless device for a wireless network.

[0004] BACKGROUND

[0005] In telecommunication industry, the 5thGeneration mobile network, 5G, has opened a new 5G spectrum for technological applications. The 5G / 6G spectrum is a range of radio frequencies and millimetre-waves, mm Waves, that carries data from User Equipment, UE, to a base station. For example, the 5G spectrum offers vast bandwidth that enables connections between the UE and the base station at a speed that was previously implausible. However, the price paid for the vast and unlimited bandwidth is an increasing number of operational frequencies. This leads to higher path losses, which in turn results in a lower signal strength at the UE side. Solutions to compensate for the higher path losses caused by the increased operational frequencies comprise firstly, to increase antenna gain fora receiver and secondly, to switch from a broadcast network to a network where energy is directed only to targeted users thus providing better signal strength to the UE.

[0006] Currently, use of phased array antennas addresses the challenges associated with the antenna gains of receivers in the phased array antennas. For example, increasing the number of elements of the phased array antennas allows for higher power / antenna gain. Further, by controlling the power and / or the phase of the phased array antennas, the energy can be redirected to the targeted users.

[0007] Nowadays, the phased array antennas generally comprise ten to hundreds of the elements. The number of elements of the phased array antennas is expected to increase to a couple of thousands. Each control point in the phased array antennas characteristically uses a dedicated electronic device to ensure correct operation of a communication system comprising the phased array antennas.

[0008] Further, depending on the architecture of Frequency Division Duplex, FDD, Time Division

[0009] Duplex, TDD, etc, the electronic devices that may be used in the phased array antennas may include mixers, power amplifiers, low-noise-amplifiers, and / or Radio Frequency, RF, filters. These electronic devices are used for sending and receiving information / data between the UE and the base station. For example, the mixers are used to shift radio signals from one frequency range to anotherfrequency range and the power amplifiers are used to amplify the radio signal to a necessary power level for transmission to the receiver. Further, the low- noise-amplifiers are characteristically used to amplify very low-power radio signals without significantly degrading their signal-to-noise ratio and the RF filters are used to filter out noise or reduce interference of external signals that could affect the quality or performance of any communication system. However, among all the electronic devices of the base stations, especially the RF filters and the power amplifiers are characteristically costly.

[0010] For example, regarding the phased array antennas in the base stations, one power amplifier and one RF filter is characteristically required per subarray. Thus, hundreds of power amplifiers and RF filters may be used per base station. Additionally, availability of several frequency bands for the phased array antennas for operating in the same base station is becoming more and more appealing as it may contribute to sustainability and cleanliness in sites and cities. Therefore, for the base station to function in several frequency bands, a large number of electronic devices per subarray of phased array antennas may be needed. This may increase cost and power consumption.

[0011] Thus, for these reasons, the RF filters for the 5G / 6G should comply with a dual / multiband operation while at the same time provide for low-cost operation.

[0012] SUMMARY

[0013] In view of the above, using standard post-processing tuning / adjusting screws for fabrication of the RF filters becomes challenging due to shorter wavelengths and the higher operational frequencies bandwidth provided by the 5G or6G. Therefore, it is desirable to provide RF filters without the need for post-processing tuning or a solution that allow the post-processing tuning to be integrated into manufacturing process of the RF filters.

[0014] Thus, there is a need for providing an improved method and signal filters to overcome one or more limitations of existing filter systems. Conventionally, the RF filters designed for operating at the mmWaves, in an example range of, 30-300 GHz, belong to one of two categories, either low performance filters or high- performance filters. The RF filters may be considered as low performance filters because of their low Q-value and no capabilities of producing zeros. On the other hand, the high- performance filters such as waveguide and cavity filters may provide high performance but are expensive. Further, the RF filters with high performance usually have an increased volume / size. This makes them difficult to use in large phased array antennas, where hundreds of RF filters are mounted to the phased array antenna.

[0015] It is therefore an object of the present disclosure to provide a signal filter unit and a method for controlling energy loss during operation of the wireless device in the wireless network to mitigate, alleviate, or eliminate all or at least some of the above-discussed drawbacks of presently known solutions.

[0016] This and other objects are achieved by means of a filter unit, and a method defined in the appended claims. The term exemplary is in the present context to be understood as serving as an instance, example or illustration.

[0017] According to a first aspect of the present disclosure, a signal filter unit is provided. The signal filter unit is utilised for controlling energy loss during operation of a wireless device in a wireless network. The signal filter unit comprises at least one filter layer having at least one filter. The at least one filter has a cavity formed therein and at least one resonator arranged within the cavity. The signal filter unit comprises at least two secondary layers, wherein each secondary layer has a predefined cavity. The at least two secondary layers are arranged to enclose the at least one filter layer, wherein the predefined cavity of each secondary layer is cylindrical and is coaxial with the cavity of the at least one filter in the at least one filter layer.

[0018] Optionally, each filter of the one or more filters in the at least one filter layer comprises a three-dimensional, 3-D, high order bandpass filter.

[0019] Optionally, the cavity comprises a circular cavity, wherein a dimension of the circular cavity is selected according to a dimension of the at least one resonator.

[0020] Optionally, a material of the at least one filter layer is selected from a group comprising at least one of: metal comprising an Aluminum; or a plastic; or an invar; or any metallic alloy. Optionally, a material of the at least two secondary layers is selected from a group comprising at least one of: a metal comprising an Aluminum; or a plastic; or an invar; or any metallic alloy.

[0021] Optionally, the at least one filter layer comprises a plurality of filters having a plurality of resonators, and wherein a number of resonators in the plurality of resonators are equal to a number of poles in the filter unit.

[0022] Optionally, the at least one resonator comprises a rectangular resonator, wherein a material of the at least one resonator is selected from a metal comprising aluminum.

[0023] Optionally, the one or more filter layers are oriented in a predefined direction in the filter unit, wherein the predefined direction is selected as one of a horizontal direction or a vertical direction.

[0024] Optionally, at least connector to connect the least one resonator to one or more components in the wireless device, wherein the one or more components comprises at least one of an antenna and a power amplifier.

[0025] Optionally, at least one filter layer is interleaved between the at least two secondary layers through one or more connecting units, wherein the one or more connecting units are arranged to pass through one or more holes provided in each of: the secondary layer and the at least one filter layer, wherein the one or more connecting units are selected from a group comprising at least one of: alignment pins or alignment screws.

[0026] Optionally, the at least two second layers are arranged at, at a position over the at least one filter layer and below the at least one filter layer, wherein the at least two secondary layers are provided for each filter layer from a plurality of filter layers, and wherein a geometry of each secondary layer from the at least two secondary layers is identical.

[0027] Optionally, a plurality of cavities in the plurality of filters are circular cavities having one of a same value of diameter or different values of diameter.

[0028] Optionally, the at least two filter layers from the plurality of filter layers are connected through a T-junction to create a diplexer for one of a dual band or multi-band application in the wireless network. Optionally, the at least one filter layer is coated with a coating material, wherein the coating material is selected from a group of metals comprising gold, silver, copper, aluminium, tungsten, nickel, paliney, or molybdenum.

[0029] Optionally, each filter has one or more poles of frequencies to filter an incoming signal at one or more frequencies, wherein a number of resonators in the at least one filter layer are equal to a number of poles in the at least one filter layer.

[0030] Optionally, the signal filter unit comprises an input port for receiving an incoming signal to be filtered through the filter unit. The signal filter unit comprises an output port for generating a filtered signal, wherein each of the input port and the output are embedded in at least one secondary layer of the at least two secondary layers.

[0031] According to a second aspect of the present disclosure, a method for fabricating a signal filter unit for use in controlling energy loss during operation of a wireless device in a wireless network is provided. The method comprises fabricating at least one filter layer having at least one filter. The fabricating comprises forming a cavity in the at least one filter. The fabricating comprises arranging at least one resonator within the cavity. Further, the method comprises fabricating at least two secondary layers. The fabricating comprises forming a predefined cavity in each secondary layer. The fabricating comprises arranging the at least two secondary layers to enclose the at least one filter layer, wherein the predefined cavity of each secondary layer is cylindrical and is coaxial with the cavity of the at least one filter in the at least one filter layer.

[0032] According to a third aspect of the present disclosure, a filter layer in a signal filter unit is provided. The signal filter unit is for use in controlling energy loss during operation of a wireless device in a wireless network. The filter layer comprises at least one filter which has a cavity formed therein and at least one resonator arranged within the cavity. The filter layer comprises at least two secondary layers, wherein each secondary layer has a predefined cavity. The at least two secondary layers are arranged to enclose the at least one filter layer, wherein the predefined cavity of each secondary layer is cylindrical and is coaxial with the cavity of the at least one filter in the at least one filter layer.

[0033] According to a fourth aspect of the present disclosure, there is provided a computer program product comprising a non-transitory computer readable medium, having thereon a computer program comprising program instructions. The computer program is loadable into a data processing unit and configured to cause execution of the method according to the first and second aspects when the computer program is run by the data processing unit.

[0034] Some embodiments disclosed herein have one or more of the following advantages:

[0035] - an arbitrary number of bandpass filters may be fabricated at once, reducing cost and assembly labor.

[0036] - the combination of two dimensional, 2D resonator layers or the filter layers with three- dimensional, 3D coaxial cavities, providing accuracy in fabrication. Thereby, RF filters tuned directly at fabrication may be provided.

[0037] - The proposed signal filter unit is designed based on a vertical positioning approach of the RF filters in the signal filter unit. This eases the integration of the RF filters with the phased array antenna. This vertical multilayer approach facilitates integration of the signal filter unit with radio components as it may be easily connected to the phased array antenna and match a required footprint of a subarray feeding network of the phased array antennas.

[0038] - In addition to single band operation, the signal filter units may be also used for a dualband operation by connecting multiple filters at a junction.

[0039] - The proposed method provides easier design, easy fabrication and easy assembly. For instance, galvanic connection of input and output in the filter unit may be easily done from a back side of the filter layer / resonator layer of the RF filter. Accordingly, post processing tuning can be avoided.

[0040] - The planar resonators in the filters may be fabricated through planar technology such as water jet cut, EDM, milling, etc., which provides better accuracy with respect to the 3D resonators and also reduces overall cost of filters.

[0041] - The proposed signal filter unit may include resonators that are rectangular in shape and enclosed within the cavity of the filter layer. These filter layers with the rectangular resonator are interleaved with secondary layers having circular cavity / cylindrical cavity / air cylindrical cavity, which produces high Q-values, i.e., >2000. As the circular cavity / cylindrical cavity is used in the RF filters and the dimensions are small in term of the wavelength, the 5G spectrum is free of spurious modes up to at least twice the central frequency. In the particular example the next mode appears after 30 GHz. - The proposed signal filter unit can be arranged with several resonators in the same layer. The several filters can be fabricated at once and produce a modular approach n x n band-pass filter. This reduces building practice challenges and cost, basically the assembly cost is the same for one than for n x n filters.

[0042] - The RF filter may be fully metallic. At least in this case, it may provide a good power handling, low losses, i.e., less than 0.5dB at center frequency for 5 poles at ku-band including the connectors. The RF filter can also be used as heat sink for 5G / 6G base stations where many power amplifiers can be connected to the RF filters via coins. The metal-based RF filter can have pipe channels where airor liquid can be used forcooling purposes.

[0043] - if dual band is desired, a T-junction or an extra node can be used to create a diplexer through multiple filters.

[0044] - When the signal filter unit is fully metallic, aluminum may be used with silver coating. produce Q values over 2000 for frequencies ranging from 10 to 15GHz due to circular cavity arrangement in the filter layers.

[0045] - The proposed dual / multiband RF filters have a total size / volume lower than the size of the subarray antenna of the phased array antennas which eases integration of the RF filters with the electronic devices.

[0046] - Additionally, when the applications coexist with other technological applications, the proposed design of the RF filters for the application include / incorporate zeroes to improve the rejection caused due to out- of-bandpass signals. Thus, the proposed RF filters with zeros are crucial in bandpass filters and duplex functionality applications where certain specifications are required.

[0047] Other advantages may be readily apparent to one having skill in the art. Certain embodiments may have none, some, or all of the recited advantages.

[0048] BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The foregoing will be apparent from the following more particular description of the example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the example embodiments. FIG. 1 discloses an example of a wireless communication system;

[0050] FIG. 2 discloses a block diagram of an example signal filter unit for controlling energy loss during operation of wireless device in the wireless network;

[0051] FIG. 3 discloses a schematic diagram of the signal filter unit for controlling energy loss during operation of wireless device in the wireless network;

[0052] FIG. 4 discloses a schematic diagram of an example of the signal filter unit for providing integrated communication system;

[0053] FIG. 5 discloses an example of different units of a signal filter unit arranged in a stack for controlling energy loss during operation of wireless device in the wireless network;

[0054] FIG. 6 is a flowchart illustrating example steps for a method for controlling energy loss during operation of wireless device in the wireless network;

[0055] FIG. 7 discloses a schematic diagram for fabrication of the signal filter unit;

[0056] FIG. 8 discloses a schematic diagram for fabrication of a dual-bandpass filter from the signal filter unit;

[0057] FIG. 9 illustrates graph showing simulation result of signal filter unit for mmWaves;

[0058] FIGS. lOa-lOb illustrates graphs showing various results for controlling energy loss during operation of wireless device in the wireless network; and

[0059] FIG. 11 discloses an example computing environment.

[0060] DETAILED DESCRIPTION

[0061] Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The apparatus and methods disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

[0062] The terminology used herein is for the purpose of describing particular aspects of the disclosure only and is not intended to limit the invention. It should be emphasized that the term "comprises / comprising" when used in this specification is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0063] Embodiments of the present disclosure will be described and exemplified more fully hereinafter with reference to the accompanying drawings. The solutions disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0064] It will be appreciated that when the present disclosure is described in terms of a platform and a method, it may also be embodied in one or more processors and one or more memories coupled to the one or more processors, wherein the one or more memories store one or more programs that perform the steps, services and functions disclosed herein when executed by the one or more processors.

[0065] FIG. 1 discloses an example wireless communication system 100. Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the examples disclosed herein are described in related to a wireless communication system / wireless network, such as the example wireless communication system 100 described in FIG. 1.

[0066] The wireless communication system 100 may comprise and / or interface with any type of communication, telecommunication, data, cellular, and / or radio network or other similar type of system. The wireless communication system 100 may be configured to operate according to specific standards or other types of predefined rules of procedures. Thus, the wireless communication system 100 may implement communication standards, such as, but not limited to, global system for mobile communications, GSM, universal mobile telecommunications system, UMTS, long term evolution, LTE, and / or other suitable 2G, 3G, 4G, or 5G standards, wireless local area network, WLAN, standards such as, IEEE 802.11 standards, and / or any other appropriate wireless communication standards, such as, worldwide interoperability for microwave access, WiMax, Bluetooth, Z-Wave and / or ZigBee standards.

[0067] For simplicity, as depicted in FIG. 1, the wireless communication system 100 comprises a signal filter unit 200, a network node 104, and a network 106. The signal filter unit 200 and the network node 104 operate together in order to provide wireless connections in the wireless communication system 100. The network 106 may comprise one or more backhaul networks, core networks, IP networks, public switched telephone networks, PSTNs, packet data networks, optical networks, wide-area networks, WANs, local area networks, LANs, wireless local area networks, WLANs, wired networks, wireless networks, metropolitan area networks, and other networks to enable communication between devices (for example, wireless devices and a network node).

[0068] The network node 104 may refer to equipment capable, configured, arranged, and / or operable to and / or with other network nodes or equipment in the wireless communication system 100 to enable and / or provide wireless access and / or to perform other functions (for example, administration) in the wireless communication system 100. Examples of the network node 104 include, but are not limited to, access points, Aps (for example, radio access points), base stations, BSs (for example, radio base stations, nodeBs, evolved NodeBs, eNBs, new radio, NR, nodes (gNBs), or the like). The BSs may be categorized based on an amount of coverage the BSs provide (or, stated different, their transmit power level) and may then also be referred to as femto BSs, pico BSs, micro-BSs, macro-BSs. The BS may be a relay node or a relay donor node controlling a relay.

[0069] The signal filter unit 200 may refer to a device capable, configured, arranged and / or operable to communicate wirelessly with the network node 104 and / or other wireless devices.

[0070] In some examples, the wireless devices may include one or more of: computing devices, wireless devices, ultra-low power wireless devices, Internet of Things, loT, devices, and so on.

[0071] Examples of the computing devices may include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over Internet Protocol, IP, VoIP, phone, a wireless local loop phone, a desktop computer, a personal digital assistant, PDA, a wireless camera, a gaming console or device, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment, LEE, a laptop-mounted equipment, LME, a smart device, a wireless customer-premise equipment, CPE, a vehicle- mounted wireless terminal device, and so on.

[0072] It should be understood that the signal filter unit 200 may not be limited to the abovedescribed wireless devices. The signal filter unit 200 may be extended to other wireless devices of different classes or categories providing different services while supporting, for example, Enhanced Mobile Broadband, eMBB, massive Machine-Type Communication, MTC, Ultra-Reliable Low Latency Communication, URLLC, Time Sensitive Networking, TSN, or the like.

[0073] In the wireless communication system 100, the network node 104 and the signal filter unit 200 are connected to 3GPP 5G core network, where specific network services and operations are provided through software components called network functions, NFs. The wireless communication system 100 hosts large scale applications.

[0074] Conventionally, the RF Filters designed for operating at the mmWaves are of two categories one is low performance filters and other is high performance filters. The low performance filters are often based on standard Printed Circuit Board, PCB manufacturing process and may use techniques such as planar filters or suspended stripline technologies. The RF filters may be low performance filters because of their low Q-value and no capabilities of producing zeros. On the other hand, the high-performance filters such as waveguide and cavity filters may provide high performance but are expensive. Further, the RF filters with high performance is usually related to an increased volume / size which make the RF filters difficult to be used in large, phased array antennas where hundreds of RF filters, i.e., one per subarray, are required to fit under the same phased array antenna.

[0075] Thus, the present disclosure presents a wireless communication network 100, a network node 104 and a filter unit 200, wherein the filter unit 200 is adapted for fabricating filter unit for operating a base station by reducing the time consumption.

[0076] FIG. 2 discloses a schematic diagram illustrating an example signal filter unit 200 for controlling energy loss during operation of the wireless device in the wireless network 106 according to some embodiments.

[0077] The signal filter unit 200 comprises at least one filter layer 202 having at least one filter 204. The at least one filter 204 has a cavity 206 formed therein and at least one resonator 208 arranged within the cavity 206. The signal filter unit 200 comprises at least two secondary layers 210, wherein each secondary layer 210 has a predefined cavity 212. The at least two secondary layers 210 are arranged to enclose the at least one filter layer 202, wherein the predefined cavity 212 of each secondary layer 210 is cylindrical and is coaxial with the cavity of the at least one filter 204 in the at least one filter layer 202.

[0078] Optionally, each filter of the one or more filters 204 in the at least one filter layer 202 comprises a three-dimensional, 3-D, high order bandpass filter.

[0079] Optionally, the cavity 206 comprises a circular cavity, wherein a dimension of the circular cavity is selected according to a dimension of the at least one resonator 208.

[0080] Optionally, a material of the at least one filter layer 202 is selected from a group comprising at least one of: metal comprising an Aluminum; or a plastic; or an invar; or any metallic alloy.

[0081] Optionally, a material of the at least two secondary layers 210 is selected from a group comprising at least one of: a metal comprising an Aluminum; or a plastic; or an invar; or any metallic alloy.

[0082] Optionally, the at least one filter layer 202 comprises a plurality of filters having a plurality of resonators, and wherein a number of resonators 208 in the plurality of resonators are equal to a number of poles in the signal filter unit 200.

[0083] Optionally, the at least one resonator 208 comprises a rectangular resonator, wherein a material of the at least one resonator 208 is selected from a metal comprising aluminum.

[0084] Optionally, the one or more filter layers 202 are oriented in a predefined direction in the signal filter unit 200, wherein the predefined direction is selected as one of a horizontal direction or a vertical direction. For example, to include zeros in the one or more filter layers 202 of the signal filter unit 200, the at least one resonator 208 of the one or more filter layers 202 should not be aligned in the predefined direction, when the at least one resonator 208 is in different filter layers 202. In an example, zeros are a property of transfer function of the signal filter unit 200, and generally solutions that make the transfer function tend to zero are called, zeros.

[0085] Optionally, the signal filter unit 200 comprises at least one connectorto connect the least one resonator 208 to one or more components in the wireless device, wherein the one or more components comprises at least one of an antenna and a power amplifier. Optionally, the at least one filter layer 202 is interleaved between the at least two secondary layers 210 through one or more connecting units, wherein the one or more connecting units are arranged to pass through one or more holes provided in each of: the secondary layer 210 and the at least one filter layer 202, wherein the one or more connecting units are selected from a group comprising at least one of: alignment pins or alignment screws.

[0086] Optionally, the at least two second layers 210 are arranged at, a position over the at least one filter layer 202 and below the at least one filter layer 202, wherein the at least two secondary layers 210 are provided for each filter layer 202 from a plurality of filter layers 202, and wherein a geometry of each secondary layer 210 from the at least two secondary layers 210 is identical.

[0087] Optionally, a plurality of cavities in the plurality of filters are circular cavities having one of a same value of diameter or different values of diameter.

[0088] Optionally, the at least two filter layers 202 from the plurality of filter layers 202 are connected through a T-junction to create a diplexer for one of a dual band or multi-band application in the wireless network.

[0089] Optionally, the at least one filter layer 202 is coated with a coating material, wherein the coating material is selected from a group of metals comprising gold, silver, copper, aluminium, tungsten, nickel, paliney, or molybdenum.

[0090] Optionally, each filter has one or more poles of frequencies to filter an incoming signal at one or more frequencies, wherein a number of resonators in the at least one filter layer 202 are equal to a number of poles in the at least one filter layer 202.

[0091] Optionally, the signal filter unit comprises an input port for receiving an incoming signal to be filtered through the filter unit. The signal filter unit comprises an output port for generating a filtered signal, wherein each of the input port and the output are embedded in at least one secondary layer 210 of the at least two secondary layers 210.

[0092] In an example, FIG. 2 is further explained in detail with additional information. FIG. 2 shows the signal filter unit 200. The signal filter unit 200 comprises the at least one filter layer 202. The at least one filter layer 202 comprises a filter 204, a cavity 206 with a resonator 208. The signal filter unit 200 further comprises a first secondary layer 210 and a second secondary layer 210. The first secondary layer 210 comprises a predefined cavity 212 and the second secondary layer 210 comprises a predefined cavity 212. The predefined cavity 212 are circular cavity creating a kind of coaxial cavity.

[0093] The at least one filter layer 202 comprising the filter 204 has the cavity 206 which is formed in the filter 204 and the resonator 208 is arranged within the cavity 206. Further, the first secondary layer 210 and the second secondary layer 210 are arranged / interleaved to enclose the at least one filter layer 202 as show in FIG. 2. The predefined cavity 212 of both the first secondary layer 210 and the second secondary layer 210 is cylindrical and is coaxial with the cavity 206 of the filter 204 in the at least one filter layer 202. Furtherthe signal filter unit 200 as shown in FIG. 2 comprises an input port 214 and an output port 216. The input port 214 is configured to receive incoming signal to be filtered through the signal filter unit 200. The output port 216 is configured to generate the filtered signal. In an example, both the input port 214 and the output port 216 are embedded in the first secondary layer 210 and the second secondary layer 210, respectively.

[0094] Further, in an example, the signal filter unit 200 uses material such as aluminum, or plastic or invar or any metallic alloy for the at least one filter layer 202 to produce an assembled 3-D high order bandpass filter. The at least one filter layers 202 includes plurality of filters 204 which in turn comprises the plurality of resonators 208. The number of resonators 208 in the plurality of resonators 208 are equal to the number of poles in the signal filter unit 200. Further, the final number of poles will be equal to the number of filter layers 202 that include resonators 208. In another example, the at least one filter layers 202 having the plurality of filters 204 with the resonators 208 may include as many resonators 208 as needed / required, i.e., n resonators, from different bandpass filters, so once assembled n x n bandpass filters 204 are obtained. This approach of fabricating the signal filter unit 200 may reduce the cost and weight as the n x n bandpass filters 204 may be manufactured with the same effort of manufacturing one bandpass filter.

[0095] Further in an example, as the at least one filter layers 202 with the resonator 208 are in 2D, the accuracy is better controlled, allowing to fabricate the signal filter unit 200 that are already tuned. FIG. 3 discloses a schematic diagram of an example of the signal filter unit 200 for controlling energy loss during operation of wireless device in the wireless network 106.

[0096] FIG. 3 shows the detailed diagram of the signal filter unit 200 and components of the signal filter unit 200. In FIG. (A) snippet in FIG. 3 illustrates the signal filter unit 200, (B) illustrates the components of the signal filter unit 200 and (C) illustrates unit cell of a single filter 204 in signal filter unit 200.

[0097] Additionally, (A) of FIG. 3 shows a simple example of the signal filter unit 200. The signal filter unit 200, comprises 4 independent filter layers 202. All the 4 independent filter layers 202 are oriented in vertical direction. Each of the filter layers 202 has two ports called the input port 214 and the output port 216, as shown in FIG. 2. In an example, both the input port 214 and the output port 216 are symmetrical. In an example, the input port 214 and the output port 216 may be embedded in outer metallic layers, i.e., the secondary layers 210 to offer a cleaner and more compact prototype. In an example, the input port 214 and the output port 216 may be a coaxial connector utilized for being embedded in the at least one secondary layer 210 of the at least two secondary layers 210. In another example, the input port 214 and the output port 216 may utilise a coupling mechanism, such as capacitive or inductive for being embedded in the at least one secondary layer 210 of the at least two secondary layers 210. Further, the signal filter unit 200 comprises 5 poles, i.e., five layers of the resonator 208, also referred as the filter layers 202 in horizontal direction.

[0098] Additionally, (B) of FIG. 3 shows the components of the signal filter unit 200. In (B), each of the filter layer 202 comprises at least one filter 204. The at least one filter 204 comprises the cavity 206, and at least one resonator 208 as shown in (C) of FIG. 3. In an example, the at least one resonator 208 may be rectangular and 2D in shape.

[0099] In another example, dimensions of the cavity 206 of the filter layer 202 may be adjusted according to the required bandpass filter 204 and thickness of the at least one resonator 208. Further, depending on fabrication method, type of input coupling, i.e., capacitive or inductive and type of chamfer for corners of the at least one resonator 208 may be chosen / selected.

[0100] FIG. 4 discloses a schematic diagram of an example of the signal filter unit 200 for providing integrated communication system. FIG. 4 shows how the signal filter unit 200 may be used to produce high integrated systems. In this case two signal filter unit 200 may be connected through Printed Circuit Board, PCB feeding networks 404 to one dual polarized antenna 400 as shown in FIG. 4. In an example, on the bottom side of the signal filter units 200, power amplifier 402 and control of the integrated system may be backed up. Further, as the signal filter unit 200 is intended to be used for 5G / 6G, hundreds of the signal filter unit 200 would be required. Since, the signal filter unit 200 is used in 5G / 6G every signal filter unit 200 needs to handle few watts and some percentage of power will be translated into heat in the environment. In another example, as the signal filter unit 200 is fully metallic, some heat may be dissipated without disturbing the performance of the signal filter unit 200. Further, the two-signal filter unit 200 connected through PCB feeding networks 404 to the dual polarized antenna 400 forms the bandpass filter 406, as shown in FIG. 4.

[0101] FIG. 5 discloses an example of different units of the signal filter unit 200 for controlling energy loss during operation of wireless device in the wireless network 106. FIG. 5shows the at least one filter layer 202, the at least one filter 204, the cavity 206 and the at least one resonator 208. FIG. 5 also shows at least one alignment pins or alignment screws 218. In an example, FIG. 5 shows one fabricated 4 x 4 single band-pass filter 200. In this case, all the filter layer 202 are silver coated before assembly process. In another example, connectors / one or more connecting units may be screwed into the input port 214 and the output port 216, as shown in FIG. 2, of the two secondary layers 210, also referred as thick metallic layers. Upon screwing the connectors / the one or more connecting units, the filter layers 202 with the resonator 208 may be easily soldered. Further, FIG. 5 shows several signal filter units 200, each of them with 4 x 4 = 16 bandpass filters 204.

[0102] FIG. 6 is a flowchart illustrating example steps for a method for controlling energy loss during operation of wireless device in the wireless network 106. The method 500 is performed for fabricating the signal filter unit 200 for use in controlling energy loss during operation of the wireless device in the wireless network 106.

[0103] At step 502, the method 500 comprises fabricating the at least one filter layer 202 having the at least one filter 204. Further, the fabricating comprises forming the cavity 206 in the at least one filter 204 and arranging the at least one resonator 208 within the cavity 206. At step 504, the method 500 comprises fabricating the at least two secondary layers 210. The fabricating comprises forming the predefined cavity 212 in each secondary layer 210 and arranging the at least two secondary layers 210 to enclose the at least one filter layer 202. The predefined cavity 212 of each secondary layer 210 is cylindrical and is coaxial with the cavity 206 of the at least one filter 204 in the at least one filter layer 202.

[0104] In an example, the at least one resonator 208 is fabricated using water jet cut, electromagnetic discharging method EDM or any other method that allows to create the at least one resonator 208 from the at least one filter layer 202.

[0105] In another example, the at least one resonator 208 may be fabricated / manufactured using a method that is selected from a group comprising at least one of water jet cut, and Electromagnetic Discharging Method, EDM. In FIG. 3, the at least one resonator 208 is fabricated by the waterjet cut on the thin metallic layer / the at least one filter layer 202 which has a thickness t of 0.5 mm. In an example, geometry of the at least resonator 208 is synthesized using eigenmode analysis for the final signal filter unit 200. Further, once the geometry of the at least one resonator 208 for every filter layer 202 is retrieved using the eigenmode analysis or other available approaches the signal filter unit 200 can be fabricated in aluminium.

[0106] FIG. 7 discloses a schematic diagram for fabrication of signal filter unit. For example, Fig 7. shows for simplicity all the separated pieces or the components for a 4 x 4 signal filter unit 200. Upon fabrication, the final assembly of the 4 x 4 signal filter unit 200 will have 16 bandpass filters 204. In FIG. 7, the 4 secondary layers 210, also referred as thick layers are shown on left side and 2 secondary layers 210 are shown on right. Each of the secondary layers 210 comprises 4 x 4 predefined cavity 212 or also referred as circular holes. In this case, the predefined cavity 212 have been milled. Further, the resonator 208 of the filters 204 are located in the filter layers 202 / thin layers. As shown in FIG. 7, 3 of the filter layers 202 are on the centre and 2 of the filter layers 202 are on the right side. Further, in FIG. 7 two alignment pins 218 and the one or more connecting units 220 are shown. The two alignment pins 218 help in the assembly process and fastened screws to fix the final assembly of the signal filter unit 200. Additionally, all parts or the components required for the assembly of 4 x 4 signal filter units 200, comprises 5 poles. In this scenario, the 4 thick metallic layers / the secondary layers 210, includes 4 x 4 circular cavities / the predefined cavity 212. In the centre the 3 thin metal layers / filter layers 202 have 4 x 4 circular cavities 206 with the resonator 208 that are interleaved with the thick layers / secondary layers 210 as shown on the left side of FIG. 7. Further, the two extra thick metal layers / secondary layers 210 with the circular cavities / the predefined cavity 212 and two extra metal thin layers / filter layers 202 with resonator 208 are soldered with the small SubMiniature version A, SMA connectors / the one or more connecting units 220. Finally, there are extra holes in all the filter layers 202 and the secondary layers 210 that is used with fastened screws and the alignment pins 218 to fix all the components together.

[0107] In another example, a detailed explanation of the fabrication of the signal filter unit 200 is provided. The fabrication process of the signal filter unit 200 has two main components: first, thick layers / secondary layers 210 that have only cylindrical holes, i.e., the predefined cavity 212. In an example, the predefined cavity 212 may be straight cylindrical in shape or circular cylindrical in shape, this makes the predefined cavity 212 connecting and coaxial to the resonator layer / filter layer 202. Thus, currents passing through the filter layers 202 and the secondary layers 210 do not see a change in the shape of the cavity layer by layer. Second, thin layers / filter layers 202 that include the rectangular resonators 208. In an example, number of resonator layers R or the filter layers 202 are identical to the number of poles of the designed signal filter unit 200. In another example, the number of thick metal layers / the secondary layers 210 are equal to the number of resonator layers / the filter layers 202 plus two external layers, R+2.

[0108] In an example, both components, i.e., the filter layers 202 and the secondary layers 210 can be fabricated in aluminum, invar, or any metallic allow. In an alternative example, both components, i.e., the filter layers 202 and the secondary layers 210 can be fabricated in plastic or any other material suitable for the signal filter unit 200 based on requirement of an application. Further, the filter layers 202 and the secondary layers 210 can be coated with another metal to increase the conductivity and reduce the insertion losses of the material with which they are fabricated. Consider, if plastic is used for fabrication a metal coating is required to increase the conductivity and reduce the insertion losses. In an example, the coated material may include but is not limited to a couple of nanometers of silver, gold, or any other high conductivity material for the mm-waves.

[0109] In an example, the thick layers / secondary layers 210 may be fabricated with a milling process, casting or any process that can produce cylinder holes / the predefined cavity 212. In an example, the secondary layers 210 may be thick as a couple of millimeters depending on the desired frequency band. Further, for the thin layers / filter layers 202 a thickness of 0.5 mm in aluminum produces enough robustness. However, the thickness of the filter layers 202 can be scaled down or up depending on the properties of the chosen material for fabrication.

[0110] In another example, every thick layer / secondary layers 210 will include a defined number of cylinder holes / the predefined cavity 212, that is used for the signal filter unit and is identical to the final number of single bandpass filter. Similarly, the number of resonators 208 included in the resonator layer / filter layer 202 correspond to the final number of filters 204. The number of filters 204 in the resonator layers / filter layer 202 is identical to the number of holes / predefined cavity 212 in the thick layers / secondary layers 210. Further, both resonator layers / filter layers 202 and the thick layers / secondary layers 210 will include extra holes for fasting screws. Further, one outer layer of the secondary layers 210 needs to be threaded so the fasten screws can serve to stack up all layers, i.e., the filter layers 202 and the secondary layers 210 together.

[0111] In another example, the outer thick layers, i.e., first and last secondary layers 210, may include threads for RF connectors when the signal filter unit 200 wants to be characterized as a standalone component. In an example, certain input and output technologies can be used to ease the integration of the signal filter unit 200 with the base station components. In another example, the one or more connecting units 220 / connector can be coupled by inductive / galvanic of capacitive coupling. The capacitive coupling can be distributed, in such case the required tolerances will be eased.

[0112] In an example, the filter layers 202 that do not require any post tuning process needs a higher accuracy, thus water jet cut, laser cut, EDM or any high accurate method can be used to produce the 2D filter layers 202 through the proposed method 500. For example, when EDM is chosen, several layers / filter layers 202 may be fabricated at once as it allows to cut several layers / filter layers 202 with a total thickness of a couple of millimeters. For example, when the signal filter unit 200 is designed the first resonator layer, i.e., first filter layer 202, is normally different to the second resonator layer, i.e., second filter layer 202 and so on. Commonly, the geometry of the resonator 208 is symmetrical w.r.t. the center of the filter 204. Thus, outer layers are identical, i.e., the second filter layer 202 is identical to the second-to-last filter layer 202 and so on. Further, all the thick layers / secondary layers 210 have identical diameter for the holes, i.e., the predefined cavity 212 and are located in the same positions. In another example, the thickness of the first thick layer, i.e., first secondary layer 210 and last thick layer, i.e., last secondary layer 212 are identical. Similarly, the thickness of the second thick layer, i.e., the second secondary layer 210 and the thickness of the second-to-last thick layer, i.e., second-to-last secondary layer 212 are identical and so on. Further, all the layers, i.e., the filter layers 202 and the secondary layers 210, will include two extra holes for the alignment pins 218 independent of the final number of signal filter units 200 per batch. These two alignment pins 218 will guaranty the assembly in place of all components.

[0113] Further, once all components are fabricated, the first resonator layer, i.e., the first filter layer 202 is in the bottom of the first thick layer, i.e., the first secondary layer 210 and assembled using the one or more connecting units 220. Similarly, the process is repeated for the last resonator layer, i.e., the last filter layer 202 and the last thick layer, i.e., the last secondary layer 210.

[0114] Further, once the input port 214 and output port 216 are assembled with the first and last thick layers / secondary layers 210, then the rest of the layers, i.e., the filter layers 202 and the secondary layers 210 can be assembled and fastened with the screws to complete the entire signal filter unit 200. In an example, each of the resonator layers / filter layers 202 will be in between of two thick layers / secondary layers 210. The first thin / resonator layer / filter layer 202 will be between the first thick layer / secondary layer 210 and the second thick layer / secondary layer 210. Similarly, the second thin / resonator layer / filter layer 202 will be between the second thick layer / secondary layer 210 and the third thick layer / secondary layer 210 and so on until the last thin / resonator layer / filter layer 202 is located between the second-to-last thick layer / secondary layer 210 and the last thick layer / secondary layer 210. Thereupon, the alignment pins 218 will keep all layers in place while the fastened screws add up the robustness. In another example, for low frequency mmWaves there is no need for any material to glue or cover any possible gaps between the filter layers 202 and the secondary layer 210. As, the effect of the fastened screws is enough to hold the filter layers 202 and the secondary layer 210 together. It is necessary only to apply the same pressure in every fasten screw for the low frequency mmWaves. However, for high frequency mmWaves, the air gap occurring due to the surface roughness cannot be neglected. In such a case, glue, paste or any other material to fill the air gap can be used. Such a material would be required to have high conductivity as well to reduce the insertion losses.

[0115] FIG. 8 discloses a schematic diagram for fabrication of a dual-bandpass filter 200. FIG. 8 shows how two signal filter units602 and 604. The two signal filter units 602 and 604 have identical vertical dimensions and identical number of poles, but different circular diameters, i.e., the cavity 206 and the predefined cavity 212, and resonator 208 geometry. The two signal filter units 602 and 604 can be used to produce dual-band operation. Further in an example, it is possible to design different bandpass filters 204 in same vertical multilayer structure within the signal filter units 602 and 604. In FIG. 8 a T-junction 600 is used to connect two different band, i.e., the two signal filter units 602 and 604 to create a diplexer for either dual band or multiband applications in the wireless network 106. In such a case high performance and low losses can be obtained by optimizing the design of the two band-pass filters, i.e., the two signal filter units 602 and 604 with the T-junction 600. In an alternate example, another extra resonator 208 approach can be used to create the diplexer, in such case the extra node will be included in the full metallic assembly of the signal filter unit 200. In another example, as both bandpass filters, i.e., the two signal filter units 602 and 604 have identical vertical dimensions, both can be manufactured in the same batch and modular approach of the single band filter. Further in another example, if needed zeroes can be introduced in the signal filter units 602 and 604 with no extra effort during the manufacturing process by just rotating some resonators 208 to create extra energy paths.

[0116] FIG. 9 illustrates graph showing simulation result of signal filter unit 200 for mmWaves. FIG. 9 shows an example of high-performance signal filter unit 200 that may be created with the proposed method 500 as described above. For this example, 5 poles are aligned in the vertical direction and the signal filter unit 200 has no zeroes. FIGS. lOa-lOb illustrates graphs showing various results for controlling energy loss during operation of wireless device in the wireless network through the proposed signal filter unit 200. FIGS. lOa-lOb shows the statistical analysis for 32 manufactured signal filter units 200. All the 32 signal filter units 200 have the same 5 poles / 0 zeros topology. FIGS. lOa-lOb shows the distribution in % for all samples. In FIG. 10a the group delay with a high concentration around 3 ns is shown. While, in FIG. 10b the highest insertion losses per signal filter unit 200 is shown. In FIG. 10b, the highest insertion losses per signal filter unit 200 happens at the edge of the 400MHz bandpass. In another example, very few samples of the signal filter units 200 show more than 3 dB of losses in the edge of the bandpass, with a mean of 2 dB at the edge of the bandpass.

[0117] FIG. 11 illustrates an example computing environment 1100 implementing a signal filter unit 200 and a method 500 as shown in FIGS. 2, and 6 for fabricating signal filter unit 200 for use controlling energy losses in the wireless device in the wireless network 106. As depicted in FIG. 11, the computing environment 1100 comprises at least one data processing module 1106 that is equipped with a control module 1102 and an Arithmetic Logic Unit, ALU 1104, a plurality of networking devices 1108 and a plurality Input output, I / O devices 1110, a memory 1112, a storage 1114. The data processing module 1106 may be responsible for implementing the platform and method described in FIG. 6 respectively. For example, the data processing module 1106 in some embodiments is equivalent to the controlling circuitry of the platform described above in conjunction with FIGS. 2 and 6. The data processing module 1106 is capable of executing software instructions stored in memory 1112. The data processing module 1106 receives commands from the control module 1102 in order to perform its processing. Further, any logical and arithmetic operations involved in the execution of the instructions are computed with the help of the ALU 1104.

[0118] The computer program is loadable into the data processing module 1106, which may, for example, be comprised in an electronic apparatus, such as the platform. When loaded into the data processing module 1106, the computer program may be stored in the memory 1112 associated with or comprised in the data processing module 1106. According to some embodiments, the computer program may, when loaded into and run by the data processing module 1106, cause execution of method steps according to, for example, any of the methods illustrated in FIGS. 2 and 6, or otherwise described herein. The overall computing environment 1100 may be composed of multiple homogeneous and / or heterogeneous cores, multiple CPUs of different kinds, special media and other accelerators. Further, the plurality of data processing modules 1106 may be located on a single chip or over multiple chips. The algorithm comprising of instructions and codes required for the implementation are stored in either the memory 1112 or the storage 1114 or both. At the time of execution, the instructions may be fetched from the corresponding memory 1112 and / or storage 1114 and executed by the data processing module 1106.

[0119] In case of any hardware implementations various networking devices 1108 or external I / O devices 1110 may be connected to the computing environment to support the implementation through the networking devices 1108 and the I / O devices 1110.

[0120] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements shown in FIG. 11 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

Claims

CLAIMS1. A signal filter unit (200) for use in controlling energy loss during operation of a wireless device in a wireless network (106), the signal filter unit (200) comprising: at least one filter layer (202) having at least one filter (204), wherein the at least one filter (204) has a cavity (206) formed therein and at least one resonator (208) arranged within the cavity (206); and at least two secondary layers (210) wherein each secondary layer (210) has a predefined cavity (212), wherein the at least two secondary layers (210) are arranged to enclose the at least one filter layer (202), wherein the predefined cavity (212) of each secondary layer (210) is cylindrical and is coaxial with the cavity (206) of the at least one filter (204) in the at least one filter layer (202).

2. The signal filter unit (200) according to claim 1, wherein each filter (204) of the one or more filters in the at least one filter layer (202) comprises a three-dimensional, 3-D, high order bandpass filter.

3. The signal filter unit (200) according to any of the preceding claims, wherein the cavity comprises a circular cavity, wherein a dimension of the circular cavity is selected according to a dimension of the at least one resonator (208).

4. The signal filter unit (200) according to any of the preceding claims, wherein a material of the at least one filter layer (202) is selected from a group comprising at least one of: metal comprising an Aluminum; or a plastic; or an invar; or any metallic alloy.

5. The signal filter unit (200) according to any of the preceding claims, wherein a material of the at least two secondary layers (210) is selected from a group comprising at least one of: a metal comprising an Aluminum; or a plastic; or an invar; or any metallic alloy.

6. The signal filter unit (200) according to any of the preceding claims, wherein the at least one filter layer (202) comprises a plurality of filters having a plurality of resonators, and wherein a number of resonators in the plurality of resonators are equal to a number of poles in the filter unit (200).

7. The signal filter unit (200) according to any of the preceding claims, wherein the at least one resonator (208) comprises a rectangular resonator, wherein a material of the at least one resonator (208) is selected from a metal comprising aluminum.

8. The signal filter unit (200) according to any of the preceding claims, wherein the one or more filter layers (202) are oriented in a predefined direction in the filter unit (200), wherein the predefined direction is selected as one of a horizontal direction or a vertical direction.

9. The signal filter unit (200) according to any of the preceding claims, comprising: at least connector to connect the least one resonator (208) to one or more components in the wireless device, wherein the one or more components comprises at least one of an antenna and a power amplifier.

10. The signal filter unit (200) according to any of the preceding claims, wherein at least one filter layer (202) is interleaved between the at least two secondary layers (210) through one or more connecting units (220), wherein the one or more connecting units (220) are arranged to pass through one or more holes provided in each of: the secondary layer (210) and the at least one filter layer (202), wherein the one or more connecting units (220) are selected from a group comprising at least one of: alignment pins (218) or alignment screws (218).

11. The signal filter unit (200) according to any of the preceding claims, wherein the at least two second layers (210) are arranged at, a position over the at least one filter layer (202) and below the at least one filter layer (202), wherein the at least two secondary layers (210) are provided for each filter layer (202) from a plurality of filter layers, and wherein a geometry of each secondary layer (210) from the at least two secondary layers (210) is identical.

12. The signal filter unit (200) according to any of the preceding claims, wherein a plurality of cavities in the plurality of filters are circular cavities having one of a same value of diameter or different values of diameter.

13. The signal filter unit (200) according to any of the preceding claims, wherein the at least two filter layers (202) from the plurality of filter layers are connected through a T-junction (600) to create a diplexer for one of a dual band or multi-band application in the wireless network (106).

14. The signal filter unit (200) according to any of the preceding claims, wherein the at least one filter layer (202) is coated with a coating material, wherein the coating material is selected from a group of metals comprising gold, silver, copper, aluminium, tungsten, nickel, paliney, or molybdenum.

15. The signal filter unit (200) according to any of the preceding claims, wherein each filter (204) has one or more poles of frequencies to filter an incoming signal at one or more frequencies, wherein a number of resonators in the at least one filter layer (202) are equal to a number of poles in the at least one filter layer (202).

16. The signal filter unit (200) according to any of the preceding claims, comprising: an input port (214) for receiving an incoming signal to be filtered through the filter unit (200); and an output port (216) for generating a filtered signal, wherein each of the input port (214) and the output port (216) are embedded in at least one secondary layer (210) of the at least two secondary layers (210).

17. A method of fabricating a filter unit (200) for use in controlling energy loss during operation of a wireless device in a wireless network (106), the method comprising: fabricating at least one filter layer (202) having at least one filter (204), wherein the fabricating comprises: forming a cavity (206) in the at least one filter (204); and arranging at least one resonator (208) within the cavity (206); fabricating at least two secondary layers (210), comprising: forming a predefined cavity (212) in each secondary layer (210); and arranging the at least two secondary layers (210) to enclose the at least one filter layer (202), wherein the predefined cavity (212) of each secondary layer (210) is cylindrical and is coaxial with the cavity (206) of the at least one filter (204) in the at least one filter layer (202).

18. The method according to claim 17, wherein at least one filter layer (202) is fabricated by using a method selected from a group comprising at least one of: waterjet cut, andElectromagnetic Discharging Method, EDM.

19. The method according to claims 17 or 18, wherein the at least two secondary layers (210) are fabricated by using a fabrication method selected from a group comprising at least one of: a milling process or a casting process.

20. The method according to any of the claims 17 to 19, wherein the at least secondary layers (210) are fabricated with thickness more than the at least one filter layer (202).

21. The method according to any of the claims 17 to 20, wherein the cavity comprises a circular cavity, wherein a dimension of the circular cavity is selected according to a dimension of the at least one resonator (208).

22. The method according to any of the claims 17 to 21, comprising: connecting the least one resonator (208) to at least connector to connect the filter unit (200) to one or more components in the wireless device, wherein the one or more components comprises at least one of an antenna and a power amplifier.

23. The method according to any of the claims 17 to 22, comprising: interleaving the at least one filter layer (202) between the at least two secondary layers (210) through one or more connecting units (220), wherein the one or more connecting units (220) are arranged to pass through one or more holes provided in each of: the secondary layer (210) and the at least one filter layer (202), wherein the one or more connecting units (220) are selected from a group comprising at least one of: alignment pins (218) or alignment screws (218).

24. The method according to any of the claims 17 to 23, comprising: arranging the at least two second layers (210) at least one a top position over the at least one filter layer (202) and at a bottom position below the at least one filter layer (202), wherein the at least two secondary layers (210) are provided for each filter layer (202) from a plurality of filter layers (202), and wherein a geometry of each secondary layer(210) from the at least two secondary layers (210) is identical.

25. The method according to any of the claims 17 to 24, wherein each filter (204) has one or more poles of frequencies to filter an incoming signal at one or more frequencies, wherein a number of resonators in the at least one filter layer (202) are equal to a number of poles in the at least one filter layer (202).

26. A filter layer (202) in a signal filter unit (200), wherein the signal filter unit (200) is for use in controlling energy loss during operation of a wireless device in a wireless network (106), the filter layer (204) comprising: at least one filter (204) has a cavity (206) formed therein and at least one resonator (208) arranged within the cavity (206); and at least two secondary layers (210) wherein each secondary layer (210) has a predefined cavity (212), wherein the at least two secondary layers (210) are arranged to enclose the at least one filter layer (202), wherein the predefined cavity (212) of each secondary layer (210) is cylindrical and is coaxial with the cavity (206) of the at least one filter (204) in the at least one filter layer (202).

27. A computer program product comprising a non-transitory computer readable medium, having thereon a computer program comprising program instructions, the computer program is loadable into a data processing unit and configured to cause execution of the method according to any of claims 17 through 25 when the computer program is run by the data processing unit.

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