A passive duplexer

Abstract

A passive duplexer having an electrical transmission path 1002 including a first resonator 1008 and an electrical receiver path 1004 including a second resonator 1010, each path being connected to an

Description

FIELD This disclosure relates to duplexers and multiplexers. More specifically, the disclosure relates to duplexers for use in 5G, complementary metal-oxide semiconductor (CMOS), massive multiple input multiple output (MMIMO) applications. BACKGROUND The introduction of 5G revolutionised the telecommunications industry by delivering extremely high throughput, low latency, and enhanced spectral efficiency. The development of 5G cellular networks increased interest in millimeter-Wave (mmW) and Terahertz (THz) frequencies for cutting-edge wireless applications, such as smartphones. Among all the front-end modules in smartphones, a duplexer is one of the most difficult components to design. Unfortunately, the design of duplexers is subject to more demanding requirements due to contemporary trends toward the development of multiband, higher-flexibility wireless communications. However, the real challenge is to develop a feasible approach to facilitate the on-chip integration of duplexers by overcoming miniaturisation challenges. The development of compact, affordable chipsets for 5G mobile communication systems has received ever-increasing attention. Multiple transverses and antennas are currently used in 5G chipsets. The most feasible and economical options for 5G systems appear to be Active Phased-Array Antennas (APAAs) employed in a Multiple Input Multiple Output (MIMO) signal processing and Massive MIMO (MMIMO) system. Various subarrays and multiple radio frequency (RF) front ends are used to implement the MMIMOs array. Each RF front end is likely to have a combination of components such as the Phase Shifter (PS), Power Amplifier (PA), Low Noise Amplifier (LNA), Variable Gain Amplifier (VGA), and duplexers. Miniaturising systems and their components are one of several strategies for significantly reducing system costs. 5G communication frequency bands are higher than 4G, resulting in significant signal attenuation. As a result, significant power capacity, or rather a higher quality factor, is required for the device to improve signal intensity. MMIMO, on the other hand, is used in 5G base stations to offer a broad range of spatial flexibility, resulting in an increase in the number of channels. Two duplexing techniques— Time Division Duplexing (TDD) and Frequency Division Duplexing (FDD) —are often used when duplexing is used in MM I MO chips. When using FDD, the transmitter and receiver work concurrently and share a single antenna. The duplexer, which consists of two selective filters, is therefore required for each FDD frequency band. To offer interband carrier aggregation, two duplexers must simultaneously connect to the antenna. Transceiver systems' size, weight, and area are reduced when a Single Input Single Output (SISO) antenna is shared in the transmit and receive paths. Multiple signals may be broadcast on the same frequency band in TDD systems. The Transmitter and Receiveroperate in various time slots at various time instants. Unlike TDD, FDD-type designs are more suited for beamforming MIMO systems. The duplexer must thus be included on the same complementary metal-oxide semiconductor (CMOS) chip as the other RF chain components since it is a crucial part of the RF chain. Many radar systems perform their transmit and receive operations using a single antenna. Compared to radars, which need sensitive receivers and high-power transmitters, radars need a front-end design that will connect and disconnect on a pulse-by-pulse basis. The above details outline the primary purpose of a duplexer. In its simplest form, a duplexer is a three-port device that enables transmitters and receivers operating at various frequencies to share a single antenna. Researchers have developed several passive duplexers: Waveguide-based duplexers, Microstrip-based duplexers, Microstrip-based hairpin line filters, and Surface Acoustic Wave (SAW) filter duplexers, etc. These passive duplexers have their own merits and demerits. The existing passive class of duplexers is not generally suited for on-chip implementation because of the planar structure of the present CMOS process, the compact feature size, and the types of metals utilised for on-chip connectivity. Waveguide-based duplexers are an excellent choice for high-power applications, but their large structure size makes them undesirable for on-chip integration. The flexibility to integrate with the planar structures and the simplicity of microstrip-based duplexer designs make them ideal candidates for the on-chip duplexer design. These designs have demonstrated strong performances at a lower frequency but have shown significant radiation losses at mm-wave. This renders them unsuitable for 5G and 6G applications. Hairpin line filters based on Microstrip are renowned for their high out-band rejection and simple design. However, the significant insertion loss is a drawback of this design. The passive SAW filter duplexer suffers from significant losses and is developed primarily for low-frequency communication systems. Current technology does not offer viable designs for an on-chip duplexer that is compact, low-power, and highly isolating for a 5G / 6G system. The number of duplexers incorporated on a single CMOS chip for 5G and higher technologies, as well as mmW and MMIMO phased array systems, is predicted to range from 4 to 512 or more. The preceding discussion of the background is intended only to facilitate an understanding of the present disclosure. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application. SUMMARY In accordance with an aspect of the disclosure there is provided a passive duplexer comprising: an electrical transmission path including a first resonator and an electrical receiver path including a second resonator, each path being connected to an antenna for transmitting and receiving electrical signals; wherein at least one of the first and second resonators has a chiral geometry and a fractal geometry; and wherein the first resonator has a first operating frequency and the second resonator has a second operating frequency. The first and second resonators may have a chiral geometry and a fractal geometry. The first operating frequency and the second operating frequency may be different from one another. The electrical transmission path may include a transmission channel connecting the first resonator to the antenna. The first resonator may be positioned between the antenna and the transmission channel. The electrical receiver path may include a receiver channel connecting the second resonator to the antenna. The second resonator may be positioned between the antenna and the receiver channel. The resonators may have a generally triangular shape. A length of the first resonator and a length of the second resonator may be generally parallel with the antenna. A side of the first resonator may be connected to the transmission channel and a side of the second resonator may be connected to the receiver channel. The antenna, transmission path, and receiver path, together, may create a generally arrow-shaped structure. In accordance with another aspect of the present disclosure there is provided a passive multiplexer, comprising: a plurality of electrical transmission paths, each including a resonator, connected to an antenna for transmitting electrical signals; a plurality of electrical receiver paths each including a resonator, connected to the antenna for receiving electrical signals; wherein at least one of the resonators has a chiral geometry and fractal geometry; and wherein the resonators have different operating frequencies. All the resonators may have a chiral geometry and a fractal geometry. Each electrical transmission path may include a transmission channel connecting its resonator to the antenna. The resonator connected to the antenna through the transmission channel may be positioned between the antenna and the transmission channel. The electrical receiver path may include a receiver channel connecting its resonator to the antenna. The resonator connected to the antenna through the receiver path may be positioned between the antenna and the receiver channel. The resonators may have a generally triangular shape. A length of each resonator may be generally parallel with the antenna. A side of each resonator may be connected to either the transmission channel or the receiver channel. The antenna, transmission paths, and receiver paths, together, may create a generally arrow-shaped structure. Embodiments of the technology will now be described, by way of example only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is an exemplary three-port duplexer for describing a working principle of an aspect of the present disclosure; Figure 2 shows an exemplary graph illustrating the different working modes of the three-port duplexer of Figure 1; Figure 3 illustrates an exemplary triangular microwave resonator passive based filter in accordance with an aspect of the disclosure; Figure 4 is an exemplary frequency response curve of the triangular microwave resonator passive based filter of Figure 3; Figure 5 illustrates an exemplary fractal triangular microwave resonator passive based filter in accordance with aspects of the disclosure; Figure 6 is an exemplary frequency response curve of the fractal triangular microwave resonator passive based filter of Figure 5; Figure 7 is an exemplary arrow-shaped fractal duplexer in accordance with aspects of the disclosure; Figure 8 is an exemplary frequency response curve of the arrow-shaped fractal duplexer of Figure 7; Figure 9 is an exemplary embodiment of the fractal triangular microwave passive based filter of Figure 5 employing a chiral characteristic; Figure 10 illustrates another exemplary embodiment of a fractal shaped resonator; Figure 11 Illustrates an exemplary embodiment of the fractal shaped resonator of Figure 10 including a chirality; Figure 12 is an exemplary frequency response curve of the triangular microwave passive based filter of Figure 9; Figure 13 is an exemplary schematic view of the arrow-shaped fractal duplexer of Figure 7 including a chiral characteristic; Figure 14 is an exemplary frequency response curve of the arrow-shaped duplexer of Figure 13; Figure 15 is an exemplary schematic diagram of a four port fractal chiral based multiplexer or quadplexer in accordance with aspects of the disclosure; Figure 16 is an exemplary schematic diagram of an n-multiplexer having a fractal chiral-based resonator in accordance with aspects of the disclosure; Figure 17 is an exemplary illustration of the different stages of fractal-chiral-based resonators; and Figure 18 is an exemplary frequency response curve of the fractal-chiral stages of Figure 17. DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS The present disclosure relates to a passive type duplexer for use in 5G, massive multiple input multiple output (MM I MO), and complementary metal-oxide semiconductor (CMOS) applications. The duplexer includes an electrical transmission path and an electrical receiver path connected a common antenna for transmitting and receiving electrical signals. The electrical transmission path includes a first resonator and the electrical receiver path includes a second resonator. In general, duplexers may be divided into two basic categories: active and passive. An on-chip area of an active duplexer is minimal. Active duplexers do, however, suffer from dielectric losses. This is due to transistors which are integrated into a substrate, which results in poor transistor-to-transistor isolation in that substrate. Additionally, a wideband millimetre-wave (mmW) signal routing from an antenna to the substrate through a tungsten (W) vias may provide a considerable challenge. Poor suppression of the unwanted frequency band may make the active class of duplexers unsuitable for mm-wave solutions. The passive class of duplexers has a large on-chip area; however, its merits may outweigh its demerits, which may make them a suitable choice for on-chip CMOS integration. Due to an absence of substrate coupling, passive duplexers may offer higher isolation. Additionally, passive duplexers are not biased and may be fabricated utilising single or multi-metal layers. At least one of the first and second resonators has a chiral geometry and a fractal geometry, there may very well be an embodiment of the present disclosure where the first and second resonators have a chiral geometry and a fractal geometry. It should also be noted that the first resonator has a first operating frequency and the second resonator has second operating frequency. It may be that the first and second operating frequencies differ from one another. The electrical transmission path may include a transmission channel. The transmission channel may connect the first resonator to the antenna. The electrical transmission path may also be configured such that the first resonator is positioned between the antenna and the transmission channel. Similarly, the electrical receiver path may include a receiver channel. The receiver channel may connect the second resonator to the antenna. The electrical receiver path may be configured such that the second resonator may be positioned between the antenna and the receiver channel. Having the first resonator positioned between the transmission channel and the antenna may reduce a total area occupied by the electrical transmission path and the antenna. Similarly, having the second resonator positioned between the receiver channel and the antenna may reduce the total area occupied by the electrical receiver path and the antenna. Therefore, this configuration and positioning of the first and second resonators within the transmission and receiver paths relative to the antenna may reduce the overall occupied area of the passive duplexer. In a further embodiment of the present disclosure, having the first resonator positioned between the transmission channel and the antenna and the second resonator positioned between the receiver channel and the antenna may provide the passive duplexer with a generally triangular shape. In such an embodiment, the first resonator may have a generally triangular shape and the second resonator may also have a generally triangular shape. It should be noted that the type of triangular shape is not important; the first and / or second resonators may have any one or combination of a equilateral triangle, isosceles triangle, scalene triangle, acute triangle, right triangle, and obtuse triangle. Furthermore, a length of the first resonator may be generally parallel with the antenna. Similarly, a length of the second resonator may be generally parallel with the antenna. Generally parallel should be understood to include being exactly parallel and configurations where there is margin of error of about 10 degrees. More specifically, generally parallel may be understood to be within about 5 degrees from being exactly parallel. In a further embodiment, a side of the first resonator may be connected to the transmission channel. Similarly, a side of the second resonator may be connected to the receiver channel. The transmission channel and the receiver channel may be on the periphery of the passive duplexer. In such a configuration, the antenna may be in the centre of the passive duplexer. The antenna may run through the centre of the antenna from a first end towards a second end. The transmission channel and the receiver channel may connect to the antenna at the first end and a loose portion of the antenna may be expose at the second end. It may be that the first resonator and the second resonator is located on either side of the antenna. More specifically, it may be that the passive duplexer is nearly symmetrical with the line of symmetry being at the antenna. Therefore, the antenna, transmission path, and receiver path, together, may create a generally arrow-shaped structure. Therefore, the passive duplexer may have a generally arrow-shaped structure. In yet a further embodiment of the present disclosure there may be provided a passive multiplexer including a a plurality of electrical transmission paths. The transmission paths may be similar to the transmission path as described earlies in that each transmission path includes a resonator connected to an antenna for transmitting electrical signals. The passive multiplexer includes a plurality of electrical receiver paths. The receiver paths may be similar to the receiver paths as described earlier in that each receiver path includes a resonator, connected to the antenna for receiving electrical signals. At least one of the resonators has a chiral geometry and fractal geometry. More specifically, it may be that all the resonators have a chiral geometry and a fractal geometry. The resonators have different operating frequencies. It may be that each electrical transmission path may include a transmission channel. Ther transmission channel may connect the resonator of the relevant transmission path to the antenna. Similarly, it may be that the electrical receiver path may include a receiver channel. The receiver channel may connect the resonator of the relevant receiver channel to the antenna. The resonator of the transmission channel may be positioned between the antenna and the transmission channel. The resonator of the receiver channel may be positioned between the antenna and the receiver channel. Similar to the passive duplexer described earlier, the resonators of either or both the transmission paths and the receiver paths may have generally triangular shapes. The length of each resonator may be generally parallel with the antenna. Generally parallel should be understood to be as described earlier. A side of each resonator may be connected to either the transmission channel or the receiver channel, whichever one is appropriate. It should also be appreciated that the antenna, transmission paths, and receiver paths, together, may create a generally arrow-shaped structure. Furthermore, the transmission paths, receiver paths, and antenna, together, may create a generally umbrella like structure. I the umbrella like structure, the antenna may be the centre and the transmission channels and receiver channel may be the spokes of the umbrella with the resonators represented as the material connecting the umbrella spokes. In accordance with other aspects of the present disclosure, a duplexer is presented herein, where two resonators, each tuned at different frequencies, may assist in signal transmission or reception. A common antenna may have two resonant modes tuned to a first frequencies (fl) and a second frequency (f2), respectively. The device may be in transmission mode when tuned to the first frequency and may acts as a receiver when tuned to the second frequency. In accordance with aspects of the present disclosure, a unit resonator as described herein may be triangular-shaped. The triangular shape may help decrease the size of the resonator. The triangular shape may increase the mass density of the resonator and high rejection may be achieved by detuning the resonators. Furthermore, the unit resonator may be a triangular fractal resonator. The disclosed fractal resonator may be designed under non-fractional Maxwell's electromagnetic theory. A special triangular fractal shape may be designed which may exhibit chiral properties with minor changes. Adding chirality and fractionality may improve overall mass density and high out-of-band rejection. The complete assembly that makes up the duplexer consists of two chiral-fractal resonators, a transmitter, a receiver, and a common antenna. The duplexer has resonators in the transmission and receiver path, as described earlier. For better isolation, both resonators may be detuned. Detuning the resonators can be easily achieved by the proposed fractal-chiral structure. The tunning frequency may be changed by changing the fractionality, chirality, or both without changing the overall size of the resonators. The duplexer's design may provide for adequate isolation between the received and transmitted signals to permit signal transmission and reception over the common antenna. The two chiral fractal-based resonators may create the necessary isolation between the transmitter and receiver ports. The arrowshaped duplexer's (as described earlier) complete arrangement using the chiral-fractal is disclosed herein. Due to the specialised geometry, the size of the passive device may be reduced, and the required 5G operating frequency is achieved with a much smaller-sized resonator. Chirality and fractality may be the two scaling factors. As discussed above, the size of the resonators may be reduced by introducing fractionality and chirality in the structure. These two geometrical properties may subsequently help in decreasing the overall size of the resonator. The common antenna of the duplexer may be connected to two channels. Depending on how the resonator is tuned, the duplexer can function in either a transmitter or a receiver mode. The same layout, as stated above, may combine duplexers into a compact CMOS chip. As described further below, with reference to the drawings, four output multiplexers may comprise mainly four resonators that may be coupled to a common antenna. This quadplexer may assists in providing four channels using a single common antenna. The present disclosure may intelligently cascade numerous duplexers to create a novel n-type multiplexer that may minimises loss and may increase the operating bandwidth. Access to several channels may be possible by coupling several duplexers to a common antenna. The resonators may be arranged to form a quadplexer, pentaplexer, hexaplexer, heptaplexer, octaplexer, or simply an n-multiplexer. The multiplexer is explained and described further below with reference to the drawings. Moreover, the resonator of the multiplexer may also be given a chiral fractal structure to address the miniaturisation problem and may provide numerous resonant modes with improved bandwidth. Furthermore, achieving GHz or THz frequency and working with 5G and future technologies may be made possible by increasing the stages of chiral fractals. The frequency response graph shows that the frequency shifts from right to left as the stages of chiral fractal in the resonators may increase. This shift may suggest that it is possible to employ exemplary chiral-fractal-based duplexers in the 5G and beyond technologies. Illustrative embodiments are now described. Other embodiments may be used in addition or instead. Some embodiments may be practised with additional components or steps and / or without all or some described components or steps. The present disclosure relates to the duplexer device for 5G and beyond application. The duplexer includes at least two resonators coupled to the same antenna. Two resonators may be tuned such that one permits the signal to be transmitted when tuned to a first frequency (fl), while the other, when tuned to a second frequency (f2), may allow the signal to be received. To overcome a miniaturisation problem and provide various resonant modes, the exemplary embodiments disclosed herein employ fractal-based resonator patterns. Fractal-based patterns may exhibit minimal insertion loss, high isolation, and efficiency. In the embodiments of the present disclosure, the different arrangements of fractals may also provide multiple resonant modes. The frequency may be further changed by adding new fractals within the resonator. In accordance with some embodiments, a multi-port structure (multiplexer) with many resonators and a shared antenna port for wireless communication devices is provided. The disclosed multiplexer may be a quadplexer (having 4 resonators), a pentaplexer (having 5 resonators), a hexaplexer (having 6 resonators), an octaplexer (having 8 resonators), or simply n-type multiplexer (having n-number of resonators). Such circuitry may receive a signal from a wireless communication device's antenna and direct the signal to a receiver path. Similarly, the multiplexer may route a transmitted signal to the antenna. The received and transmitted signals may be "routed" using resonators in the multi-port path structure. In embodiments of the present disclosure, the multiplexer may have a number of resonators, which may have different resonance frequencies and may have different sizes. The resonators of the multiplexer may also be chiral-fractal based. Problems with miniaturisation may be solved by such chiral fractal-based resonators. Multiple duplexers might be integrated on a single CMOS chip. An exemplary embodiment of a duplexer (100) which may facilitate bi-directional communication using a single antenna is illustrated in Figure 1. Figure 1 is shown to illustrate and describe a working principle of a three-port duplexer. The three-port duplexer includes two resonators (102,104) and a common antenna (106). Such a duplexer may offer a way for a receiver and a transmitter to share an antenna concurrently. The duplexer may be designed to provide sufficient isolation between the receive and transmission signals to allow for the transmission and reception of signals across the antenna (106). The antenna may contain two resonant modes as shown in the exemplary frequency curve of Figure 2. In the combined curve (108), the resonators (102 and 104) may be tuned to the first (fl) and second (f2) frequencies. These may then be coupled to two channels, respectively. When tuned to the first frequency (fl), the first resonator (102) may function as a transmitter (110), creating a channel between the transmitter and the antenna. When the second resonator (104) is tuned to the second frequency (f2), it may function as a receiver (112), offering a route between the antenna (106) and the receiver. It should be appreciated that there is no direct link between the receiver and the transmitter. Figure 3 shows an exemplary triangular microwave resonator (202) passive based filter in accordance aspects of the present disclosure. The resonator (202) may resonate at a certain frequency depending on the side dimensions (204, 206, 208) of the resonator, and the host material's permittivity. It may be possible to utilise a similar resonator to design a mm-Wave duplexer since it has a lower insertion loss. A frequency response curve (302) of the triangular resonator is shown in Figure 4. Normalised frequency (304) is taken along the x-axis, and normalised magnitude response (306) is taken along the y-axis. Figure 5 illustrates an exemplary fractal triangular microwave resonator (402) passive based filter in accordance with aspects of the disclosure. The fractal geometry may have a benefit of having an infinite length while still fitting into a finite space. The fractal resonator (402) may minimise insertion loss and an improve quality factor may be achieved. The resonator (402) may be designed under Maxwell's electromagnetic theory. Since fractal resonances may have self-similar geometrical structures, numerous resonances may occur throughout an operational bandwidth. As a result of the fractal geometric being repeated at many distinct scales within the duplexer structure, the duplexer may exhibit multiband or broadband behaviour. The relatively small fractal resonator design may also contribute to a reduction in the size of the duplexer. As a result, a duplexer with wideband properties might be produced in a low-profile package by utilising the fractal geometric principles. An exemplary frequency response curve (502) of the fractal triangular microwave resonator (402) passive based filter of Figure 5 is illustrated in Figure 6. Infinite return loss and zero transmission loss between the transmission path (Tx), and receiver path (Rx), and antenna ports may be features of an ideal duplexer. Additionally, a perfect duplexer may have maximum isolation between the transmitter and receiver channels. Every expense has an associated benefit; therefore, the duplexer may make a size trade-off (i.e., shrinks in size) to achieve low insertion loss and high insulation or transparency. To address the abovementioned issue, a duplexer (600) is disclosed in the exemplary embodiment illustrated in Figure 7. The duplexer design replaces an exemplary standard duplexer with a fractal resonator. Due to improved mass dimensional properties, one of the key benefits of employing fractal geometry may be that it can solve the miniaturisation problem. There are three ports on the duplexer: a transmitter port (602), a receiver port (604), and a common antenna port (606). Since duplexers provide two-way communication over a single channel by isolating the transmitter from the receiver when receiving a pulse and the receiver from the transmitter while transmitting a pulse. Therefore, two fractalbased resonators (608, 610) may provide the required isolation between the transmitter (602) and receiver ports (604). Figure 8 is an exemplary frequency response curve of the arrow-shaped fractal duplexer of Figure 7. The frequency response curve exemplifies the working of a fractal-based duplexer device. Theoretically, the receiver port must not receive any power from the transmitter port. That is why the transmitter's frequency is offset from the receiver's. The antenna of the duplexer has two resonant modes, i.e., a first frequency (fl) or (702) and a second frequency (f2) (704). In one mode, the fractal duplexer includes a fractal resonator (608) that, when set to a certain frequency fl (702), allows signals to flow from the transmitter port (602) to the antenna (606). Subsequently, in the second mode, when set to the frequency f2 (704), the fractal resonator (610) allows receiving signals to travel from the antenna (606) to the receiver (604). The fractal geometry may improve the unit filter's mass dimensional properties, which may reduce the size of the overall duplexer device. Another parameter, chirality "K", may further improve the design. The chirality may further provide control on impedance matching and may help increase the bandwidth. The chiral resonator (802) may be taken into consideration in the exemplary embodiment (800) of Figure 9. One skilled in the art can design the sub-triangles 1,2,3 such that they exhibit chirality with respect to each other and overall fractionality. The resonator (802) may exhibit improved mass dimension property compared with the (402) due to a decrease in the outer parameter and further helps to achieve the miniaturised duplexer design. Other exemplary arrangements are disclosed in the embodiment (801A) and (801B), as shown in Figures 10 and 11. The substrate can also be used to achieve fractionality (803) and chirality (809). This may provide further miniaturisation, and different combinations like a fractal-chiral, chiral-fractal, double fractal, and double chiral can be achieved depending on the requirement. An exemplary frequency response curve (900) of the triangular microwave passive based filter of Figure 9 is shown in Figure 12. Curve (902) represents the resonator's frequency response with the fractionalbased substrate. Whereas curve (904) with increased bandwidth is the resonator's frequency response with a chiral-fractal-based substrate. An exemplary schematic view of the arrow-shaped fractal duplexer of Figure 7 including a chiral characteristic is illustrated in Figure 13. The chiral fractal duplexer may contain a transmitter port (1002), a receiver port (1004), and a common antenna port (1006). Hence, the two chiral fractal-based resonators (1008, 1010) may provide the required isolation between the transmitter (1002) and the receiver ports (1004). The frequency response curve of the chiral fractal duplexer is exemplified in Figure 14. (1102) is the frequency response of the resonator (1008), and (1104) is the frequency response of the resonator (1010). Due to size and space restrictions, it has always been difficult to integrate several duplexers onto a single CMOS chip. Figure 15 shows an example embodiment (1200) illustrating a quadplexer that may address the abovementioned issue. Fitting in four duplexers within a CMOS technology is difficult but may be achievable with the exemplary geometry disclosed in the embodiment (1200). Following the same design technique employed in embodiment (1000), a 4-output multiplexer is presented herein. Four resonators (1202,1204, 1206, 1208) are coupled to a common antenna (1210) to provide the four channels. Each of the exemplary resonators is a one-port resonator. Generally, a duplexer (with one receive and one broadcast filter) comprises at most two resonators. However, one may incorporate n number of additional resonators connected to a single antenna. Additionally, it is preferable to ensure that each resonator exhibits a high impedance to every other resonator when multiple resonators share a single antenna. This guarantees that the combined load of all filters is kept minimum. The term "load" here refers to increased insertion loss via one resonator brought on by undesired signal dissipation by other resonators in the multiplexer. An exemplary n-channel multiplexer (1300) is illustrated in Figure 16. A single antenna (1306) is connected to multiple resonators. The duplexer has n-number of chiral fractal resonators. These resonators may be configured as a quadplexer, a pentaplexer, a hexaplexer, an octaplexer or simply an n-multiplexer, etc. An n-multiplexer is a word used throughout to refer to these multi-resonator arrangements. Each multiplexer's (1300) resonator is chiral fractal-based and tuned to a certain frequency. Figure 17 shows how the different stages of chiral fractals may affect the frequency of the resonators. These resonators may provide high efficiency, minimum insertion loss, and high efficiency. The disclosed embodiment's chiral fractal-based resonator (1402) resonates at a specific frequency. The resonators (1404) and (1406) show two and three-stagged chiral fractal geometry. The frequency response of (1402), (1404), and (1406) is shown in the frequency response curve (1500) of Figure 18. The frequency response graph (1502) illustrates the frequency shifts towards the left as the number of chiral fractals in the resonator grows. The present disclosure extends to a chiral fractal-filter device for use in microwave applications especially suitable for 5G and beyond frequency ranges. The chiral fractal-filter device may include a microstrip structure having a chiral triangular-shaped body. The chiral fractal-filter device may have a resonator that exhibits chirality and fractionality in any or both arrangements. The chiral fra eta I-filter device may be arranged, wherein the resonant frequency, mass dimension, bandwidth, and impedance of the resonator can be controlled by changing the fractionality and chirality of the chiral-fractal filter. The fractionality can be achieved by using a fractional substrate. The chirality can be achieved by using a chiral patterned substrate. The present disclosure further extends to a chiral fractal-duplexer device that may have an arrow-shaped microstrip structure; at least three ports; and at least two chiral fractal filters. The chiral fractal-duplexer device may have its three ports at the tips of the arrow-shaped microstrip structure. The chiral fractalduplexer device may have chiral-fractal filters that are detuned from each other. Isolation between the ports may be achieved by tunning the filters apart from each other. One port may be an antenna port, and two ports may be the receiver and transmitter ports. The substrate of the duplexer can be fractal, chiral or simple, depending on the requirement. The present disclosure further extends to a chiral fractal-quadplexer device, that may include a crossshaped or plus-shaped microstrip structure; at least five ports; and at least four chiral fractal filters. The chiral fractal-quadplexer device may have four ports that are at the tips and one port at the centre of the microstrip structure. The chiral fractal-quadplexer device may have its chiral-fractal filters detuned from each other. Isolation between ports may be achieved by tunning the filters apart from each other. One central port may be an antenna port, and four ports may be the receiver and transmitter ports. The substrate of the quadplexer can be fractal, chiral or simple, depending on the requirement. The number of filters can be increased to N number for multiplexer / s application / s. The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the technology to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure. The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the present disclosure be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the present disclosure is intended to be illustrative, but not limiting, of the scope of any accompanying claims. Finally, throughout the specification and any accompanying claims, unless the context requires otherwise, the word 'comprise' or variations such as 'comprises' or 'comprising' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A passive duplexer comprising:an electrical transmission path including a first resonator and an electrical receiver path including a second resonator, each path being connected to an antenna for transmitting and receiving electrical signals;wherein at least one of the first and second resonators has a chiral geometry and a fractal geometry; andwherein the first resonator has a first operating frequency and the second resonator has a second operating frequency.

2. The passive duplexer as claimed in claim 1, wherein the first and second resonators have a chiral geometry and a fractal geometry.

3. The passive duplexer as claimed in claim 1 or claim 2, wherein the first operating frequency and the second operating frequency are different from one another.

4. The passive duplexer as claimed in any one of the preceding claims, wherein the electrical transmission path includes a transmission channel connecting the first resonator to the antenna, wherein the first resonator is positioned between the antenna and the transmission channel.

5. The passive duplexer as claimed in any one of the preceding claims, wherein the electrical receiver path includes a receiver channel connecting the second resonator to the antenna, wherein the second resonator is positioned between the antenna and the receiver channel.

6. The passive duplexer as claimed in any one of the previous claims, wherein the first and second resonators have a generally triangular shape.

7. The passive duplexer as claimed in claim 6, wherein a length of the first resonator and a length of the second resonator are generally parallel with the antenna.

8. The passive duplexer as claimed in claim 6 or claim 7, wherein a side of the first resonator is connected to a transmission channel and a side of the second resonator is connected to a receiver channel.

9. The passive duplexer as claimed in any one of claims 6 to 8, wherein the antenna, transmission path, and receiver path, together, create a generally arrow-shaped structure.

10. A passive multiplexer, comprising:a plurality of electrical transmission paths, each including a resonator, connected to an antenna for transmitting electrical signals;a plurality of electrical receiver paths each including a resonator, connected to the antenna for receiving electrical signals;wherein at least one of the resonators has a chiral geometry and fractal geometry; and wherein the resonators have different operating frequencies.

11. The passive multiplexer as claimed in claim 10; wherein all the resonators have a chiral geometry and a fractal geometry.

12. The passive multiplexer as claimed in claim 10 or claim 11, wherein each electrical transmission path includes a transmission channel connecting its resonator to the antenna, and wherein the resonator is positioned between the antenna and the transmission channel.

13. The passive multiplexer as claimed in any one of claims 10 to 12, wherein the electrical receiver path includes a receiver channel connecting its resonator to the antenna, and wherein that resonator is positioned between the antenna and the receiver channel.

14. The passive multiplexer as claimed in anyone of claims 10 to 13, wherein the resonators have a generally triangular shape.

15. The passive multiplexer as claimed in claim 14, wherein a length of each resonator is generally parallel with the antenna.

16. The passive multiplexer as claimed in claim 14 or claim 15, wherein a side of each resonator is connected to either the transmission channel or the receiver channel.

17. The passive multiplexer as claimed in any one of claims 14 to 16, wherein the antenna, transmission paths, and receiver paths, together, create a generally arrow-shaped structure.

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