DESC:TECHNICAL FIELD
[0001] The present invention relates generally to a tunable duplexer for communication system. The disclosure more particularly relates to an electro-mechanically tunable duplexer for simultaneous transmission and reception of radio signals in communication system.
BACKGROUND
[0002] In two-way communication system, duplexer plays an important role, where it facilitates simultaneous transmission and reception of signals at different frequencies using single shared antenna. The duplexers also protect the highly sensitive receiver (Rx) circuit from getting overloaded with the high transmitter (Tx) power.
[0003] In general, duplexers use two highly selective bandpass filters with a common T-junction. One bandpass filter is placed in the transmit path providing attenuation to Rx band and another bandpass filter is placed in the receiver path to prevent Tx leakage overloading the receiver circuit. Duplexer design becomes simple when the separation between Tx frequency and Rx frequency band is wider. But due to continuous development in the technology, most of the applications demand closer separation between Tx and Rx frequency bands. In such case, duplexer designing become highly difficult and complicated and hence, there is a need to tune filters along with common T-junction to improve passband flatness and matching impedance. Duplexer with contiguous band requires single terminated filters with common junction. Design of single terminated filters are complex due to asymmetrical circuit topology. These duplexers are used in point to point or point to multi-point communication.
[0004] In radio communication involving Frequency Division Duplex (FDD) mode feature, switch fixed duplexers are replaced with tunable duplexers for signal transmission. A duplexer can be made tunable by using tunable filters and T-junction with tunable matching network. It requires several controls and becomes complex for overlapping Tx/Rx frequency band. Tunable duplexer can be designed by using a circulator at the common port which eliminates T-junction tunable matching network.
[0005] US20030048153A1titled "RF and Microwave duplexers that operate in accordance with a channel frequency allocation method" discloses a method for design of tunable duplexer which includes tunable filter based on microstrip filter loaded with variable capacitor and circulator. When the duplexer is operated in Tx mode, Rx band filter tuned to provide offset from assigned Tx frequency and vice versa.
[0006] US20040127178A1 titled "Tunable Duplexer" discloses a tunable duplexer that comprises of tunable filters and tunable phase shifters. Microstrip resonator loaded with varactor diode is used for the design of tunable filter.
[0007] US20040185795A1 titled "Electronically Tunable RF Front end" discloses a switchable duplexer containing multiple fixed bandpass filters and switches.
[0008] US20070024393A1 titled "Tunable Notch Duplexer" discloses planar microstrip loaded with Barium strontium Titanate (BST) varactors based tunable notch filter with limited tuning range.
[0009] US20070247257A1 titled "Electronically Tunable active Duplexer" discloses a planar duplexer designed using microstrip line loaded with varactor and phase shifting network.
[0010] However, the above mentioned conventional tunable duplexers have limited operating range of frequency and require several controls and becomes complex for overlapping Tx/Rx frequency bands. Thus, there is a need of tunable duplexer which can easily replace the conventional tunable duplexers and provide an improved signal transmission, low insertion loss, and high-power handling capacity.

SUMMARY
[0011] This summary is provided to introduce concepts of the invention related to an electro-mechanically tunable duplexer system, as disclosed herein. This summary is neither intended to identify essential features of the invention as per the present invention nor is it intended for use in determining or limiting the scope of the invention as per the present invention.
[0012] In accordance with an exemplary implementation of the present invention, there is provided an electro-mechanically tunable duplexer system. The system comprises: a plurality of tunable bandpass filters configured to be tuned for a predetermined range of frequencies; a plurality of stepper motors connected to the bandpass filters, and configured to tune the filters for the predetermined range of frequencies; a motor driving and controller unit connected to the stepper motors and configured to drive the stepper motors; and a circulator connected to the filters and an antenna, and configured to switch between the plurality of tunable filters, to couple the antenna to at least one of the plurality of tunable filters.
[0013] In an embodiment, the plurality of bandpass filters comprises a first bandpass filter connected to a receiver and second bandpass filter connected to a transmitter.
[0014] In an embodiment, the plurality of stepper motors comprises a first stepper motor and second stepper motor. The first stepper motor is connected to the first bandpass filter and second stepper motor is connected to the second bandpass filter.
[0015] In an embodiment, the circulator configured to switch between the first bandpass filter and the second bandpass filter for receive and transmit operation respectively.
[0016] In an embodiment, the predetermined range of frequencies is 4.4 Ghz to 5Ghz.
[0017] In an embodiment, the system further includes a programming interface to receive user inputs for tuning the bandpass filters for the predetermined range of frequencies.
[0018] In accordance with another exemplary embodiment of the present invention, a tunable bandpass filter is provided to be used in the electro-mechanically tunable duplexer system. The tunable bandpass filter comprises: one or more metallic resonators coaxially mounted on a non-conducting rod, each placed inside in a metallic elliptical casing, wherein the non-conducting rod is coupled to a stepper motor; one or more cavity metal probes placed at a front end and a rear end of the elliptical casing; one or more coaxial to stripline transitions connected to the one or more metal cavity probes, the one or more coaxial to stripline transitions further connected to a circulator and probes of a duplexer.
[0019] In an embodiment, each metallic resonator is affixed with at least two linear dual ended loads, each dual ended load being placed at a first end and a second end of the resonator respectively.
[0020] In an embodiment, the metallic elliptical casing includes a coupling window for coupling with an adjacent casing.
[0021] In an embodiment, the stepper motor is driven by a motor driving unit and controller unit to rotate non-conducting rod about its axis, to thereby rotate the resonator and configure the tunable bandpass filter for the predetermined range of frequencies.
[0022] In an embodiment, the resonator is rotatable by 450 about its axis.
[0023] In an embodiment, the predetermined range of frequencies is 4.4 GHz to 5 GHz.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0024] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and modules.
[0025] Figure 1 illustrates a block diagram of programmable electro-mechanically tuned duplexer, according to an exemplary embodiment of the present invention.
[0026] Figure 2 illustrates an electro-mechanically tuned bandpass filter, according to an exemplary embodiment of the present invention.
[0027] Figure 3 illustrates a graph depicting measured transmission response of the tunable duplexer of Figure 1 with 1dB cross over (C1) between transmit and receive frequency bands, according to an exemplary implementation of the present invention.
[0028] Figure 4 illustrates a graph depicting measured transmission response of the tunable duplexer of Figure 1 with 3dB cross over (C2) between transmit and receive frequency bands, according to an exemplary implementation of the present invention.
[0029] Figure 5 illustrates a graph depicting measured transmission response of the tunable duplexer of Figure 1 with 20dB cross over (C3) between transmit and receive frequency bands, according to an exemplary implementation of the present invention.
[0030] Figure 6 illustrates a graph depicting measured transmission response of the tunable duplexer of Figure 1 with 40dB cross over (C4) between transmit and receive frequency bands, according to an exemplary implementation of the present invention.
[0031] Figure 7 illustrates a graph depicting measured transmission response of the tunable duplexer of Figure 1 with fixed Tx frequency and varying Rx frequency, according to an exemplary implementation of the present invention.
[0032] Figure 8 illustrates a graph depicting measured transmission response of the tunable duplexer of Figure 1 with fixed Rx frequency and varying Tx frequency, according to an exemplary implementation of the present invention.
[0033] Figure 9 illustrates a flow chart for method of testing and programming tunable duplexer of Figure 1, according to an exemplary implementation of the present invention.
[0034] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.
DETAILED DESCRIPTION
[0035] The various embodiments of the present invention describes about a system for electro-mechanically tunable duplexer with overlapping/non-overlapping frequency bands.
[0036] In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
[0037] However, the systems and methods are not limited to the specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the presently invention and are meant to avoid obscuring of the presently invention.
[0038] It should be noted that the description merely illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
[0039] The present invention provides an electro-mechanically tunable duplexer for C band frequencies. In particular for the range of 4.4 GHz to 5GHz. The electro-mechanically tunable duplexer disclosed herein is designed to provide high selectivity with closer separation between Rx and Tx frequencies, along with low insertion loss for high power applications, whereby the transmit and the receive frequency bands can be overlapped without degrading the common port matching.
[0040] Referring to figure 1, the block diagram representing a programmable electro-mechanically tunable duplexer system (100), is illustrated. The system (100) transmits and receives a signal simultaneously using single shared antenna. The electro-mechanically tunable duplexer system (100) comprises a plurality of tunable bandpass filters (102, 103), a plurality of stepper motors (104, 105), a motor driving and controller unit (106), a circulator (101), an antenna (111), a receiver terminal (108), and a transmitter terminal (109).
[0041] The plurality of tunable bandpass filters typically includes at least two tunable bandpass filters denoted by a tunable bandpass filter 1 (TBF1) (102) and a tunable bandpass filter 2 (TBF2) (103). Each of the TBF1 (102) and TBF2 (103) is configured to be tuned for a predetermined range of frequencies. The TBF1 is connected to the receiver terminal (108) and to the circulator (101). Further, the TBF2 is connected to transmitter terminal (109), and to the circulator (101). Thus, the both the TBF1 and TBF2 are connected to the circulator (101) forming a common junction (110).
[0042] The plurality of stepper motors typically includes at least two stepper motors denoted by a stepper motor 1 (SM1) (104) and a stepper motor 2 (105). Each of the SM1 (104) and SM2 (105) is coupled with the respective TBF1 (102) and TBF2 (103) to rotate resonator(s) (shown in figure 2) of the TBF1 and the TBF2, to configure the filters for predetermined frequency range.
[0043] The circulator (101) is a three terminal device placed at the common junction (110), wherein one terminal of the circulator is connected to the antenna (111), second terminal of the circulator is connected to the TBF1 (102), and third terminal is connected to the TBF2 (103). At time of radio communication operation, the circulator isolates the receiver terminal (108) while connecting the transmitter terminal (109) and the antenna (111), to perform the transmission operation; and to perform receiving operation, the circulator isolates the transmitter terminal (109) and connects the receiver terminal (108) and the antenna (111).
[0044] The system (100) further comprises a programming interface (107) to receive user inputs. The programming interface (107) is connected to the motor drive and controller unit (106). Based on the user inputs received at the programming interface, the motor drive and controller unit (106) will process the user input and will drive the stepper motors (SM1 and SM2) (104 and 105) to configure the TBF1 (102) and TBF2 (103) for the predetermined range of frequencies.
[0045] In an embodiment, the motor drive and controller unit (106) configures each of the TBF1 (102) and TBF2 (103) independently. In another embodiment the motor drive and controller unit configures each of the TBF1 (102) and TBF2 (103) simultaneously, by driving the respective stepper motors (SM1 and SM2) (104 and 105) simultaneously.
[0046] Referring to figure 2, an electro-mechanically tunable bandpass filter (200) is illustrated. The filter (200) typically used in the electro-mechanically tunable duplexer system (100) of figure 1. The electro-mechanically tunable bandpass filter (200) comprises a plurality of elliptical metal casings (204) wherein each of the elliptical metal casing includes at least one metallic resonator (206), one or more metal cavity probes (203), and one or more coaxial to stripline transitions (202). The electro-mechanically tunable bandpass filter further comprises a non-conducting rod (208), wherein the one or more metallic resonators (206) are coaxially mounted on the non-conducting rod (208) and are placed inside each of the elliptical metal casing (204). Further, the non-conducting rod (208) is coupled to a stepper motor for rotating the non-conducting rod (208) about its axis, thereby rotating the resonators (206) within the casing (204), as the resonators (206) is/are coaxially mounted on the non-conducting rod (208). The metallic casing (204) includes a coupling window (205) for coupling with an adjacent elliptical metal casing. The one or more metal cavity probes (203) are placed at a front end and a rear end of the elliptical metallic casings (204) for measuring the resonance frequency in the elliptical casing (204) occurred due to rotation of the resonator (206). Typically, the metal cavity probes (203) includes at least two metal cavity probes (203), wherein the first metal cavity probe (203) is placed at the front end and the second metal cavity probe (203) is placed at the rear end of the casings (204). Further, the one or more coaxial to stripline transitions (202) is used to connect the metal cavity probes (203) to the circulator (101) and to the transmitter terminal (109) and receiver terminal (108) of the duplexer system (100). Typically, the first metal cavity probe (203) is connected the circulator (101) via the coaxial and stripline transition (202) and the second metal cavity probe (203) is connected the receiver/transmitter terminal (101) via the coaxial and stripline transition (202). The resonator (206) is affixed with at least two dual ended loads (207) at a first and a second end of the resonator (206) respectively.
[0047] The operation of the electro-mechanically tunable duplexer system (100) will now be explained with reference to figure 1 and figure 2. The system (100) is configured to be tuned for predetermined range of frequencies. In an exemplary embodiment, the present duplexer system (100) is configured to be tuned for the C-band range of frequencies i.e., 4.4 GHz to 5 GHz. The system (100) comprises plurality of tunable bandpass filters i.e., at least two bandpass filter, which are the tunable bandpass filter 1 (TBF1) (102) and the tunable bandpass filter 2 (TBF2) (103). The construction of the tunable bandpass filters (200) i.e., (TBF1 (102) and TBF2 (103)) is illustrated in Figure 2. The TBF1 (102) is coupled with the stepper motor 1 (SM1) (105) and the TBF2 (103) is coupled with the stepper motor 2 (SM2) (104). The system (100) further comprises a programming interface which receives user inputs such as, the frequency at which the user wants to configure the TBF1 (102) and TBF2 (103). The motor drive and controller unit (106) receives the user inputs form the programming interface to configure the TBF1 (102) and TBF2 (103). After receiving the user inputs, the unit (106) will drive the SM1 (104) and SM2 (105) to rotate the resonator (206) placed within the elliptical casing (204) by predetermined angle, to configuring the duplexer system (100) for the predetermined range of frequencies. On receipt of a drive signal from the unit (106), the SM1 (104) connected to the non-conducting rod (208) of the TBF1, will rotate the resonators (206) by the required angle. The rotation of the resonators (206) in the elliptical casings (204) will cause a change of resonance frequency in the elliptical casing (204) this change of resonance frequency is measured and sensed by the metal cavity probes (203) placed at the rear end of the TBF1 (102) and at the front end of the TBF1 (102). Similarly, on receipt of a drive signal from the unit (106), the SM2 (105) connected to the non-conducting rod (208) of the TBF2, will rotate the resonators (206) by the required angle. The rotation of the resonators (206) in the elliptical casings (204) will cause a change of resonance frequency in the elliptical casing (204) this change of resonance frequency is measured and sensed by the metal cavity probes (203), which is place at the rear end of the TBF2 (103) and at the front end of the TBF2 (103).
[0048] The change in the resonance frequency sensed and measured by the metal cavity probes (203) configures the electro-mechanically tunable filters (TBF1 and TBF2) (200, 102, 103) for the predetermined range of frequencies. Thus, each of the TBF1 (102) and TBF2 (103) are now configured for the required bandwidth. The TBF1 (102) and TBF2 are further connected to the circulator (101) and the transmitter terminal (109) and receiver terminal (108) of the duplexer system (100) using the coaxial to stripline transitions (202) for ease of communication within the system (100). Further, the circulator is connected to the antenna (111) and the circulator is placed at the common junction between the TBF1 (102), TBF2 (103), and the antenna (111) to couple the antenna to at least one of the TBF1 (102) and TBF2 (103).
[0049] In an exemplary embodiment, at the time of transmitting operation at the electro-mechanically tunable duplexer system (100), the circulator (101) isolates the receiver terminal (108) while connecting the transmitter terminal (109) and the antenna (111), to perform the transmission operation. At the time of receiving operation at the electro-mechanically tunable duplexer system (100), the circulator isolates the transmitter terminal (109) and connects the receiver terminal (108) and the antenna (111) to perform the receiving operation for the system (100).
[0050] In an exemplary embodiment, each of the electro-mechanically tunable bandpass filters (200) includes at least 5 resonators to configure the filter at frequency range of 4.4 GHz to 5 GHz. However, the number of resonators may vary as per requirement and with the increase in number of resonators an insertional loss may vary.
[0051] In an exemplary embodiment, the operational frequency of the electro-mechanically tunable bandpass filter (200) can be varied by rotating the resonators (206) at different angle. The maximum rotation angle for required tuning range is 45o. Thus, at 0o angle of the resonator the filter (200) will be configured at 4.4 GHz and at 45o angle of the resonator the filter (200) will be configured at 5 GHz. The tunning or the configuration of the filter can be varied by at least 1o. Further, the elliptical coupling windows (205) are designed to achieve constant bandwidth over the required tuning range and helps in proper arrangement of the resonator (206). Due to proper arrangement of the resonators (206) with high quality factor low insertion loss, high selectivity, and high-power handling capability over tunning range of the operation are achieved.
[0052] In one embodiment, the circulator (101) connecting the antenna (111), TBF1 (102), and TBF2 (103) results in improved isolation between TBF1 and TBF2, and allows overlapping and non-overlapping frequency band tunning without degradation in the passband.
[0053] In one embodiment, the TBF1 and TBF2 can be tuned at same frequency, as per user requirement, thereby meeting the demand of closer separation between transmit and receive bands for high data rate communication.
[0054] Figure 9 is a flow chart illustrating the operation of the method for the electro-mechanical tunable duplexer system (100). At step 901, 902 the TBF1 (102) and TBF2 (103) are tuned for the required bandwidth and tuning range. Once the TBF1 (102) and TBF2 (103) are tuned, a tunable duplexer is formed by connecting the said terminals of the circulator (101) to the antenna, the TBF1 (102), theTBF2 respectively, at step 903. At step 904, the SM1 (104) is connected to TBF1 and SM2 (105) is connected to TBF2. At step 905, the SM1 (104) and SM2 (105) are interfaced and controlled using the motor driver and controller unit (106) through programming interface (107). At step 906, the motor driver and controller unit (106) receives user inputs, such as the frequency range at which the system (100) should be configured, thereby the motor driver and controller unit (106) provides the drive signals to the SM1 (104) and SM2 (105) to be set at reference position to tune the TBF1 and TBF2 for the predetermined frequency range. At step 907, the electro-mechanically tunable duplexer system (100) is connected to a three port network analyzer and SM1 (104) is rotated and a data containing center frequency vs number of pulses is captured. At step 908, the electro-mechanically tunable duplexer system (100) is connected to a three port network analyzer and SM2 (105) is rotated and data containing center frequency vs number of pulses is captured. At step 909, the captured data is interpolated and at step 910, the interpolated data is stored in the unit (106). At step 911, as per user requirement a transmit frequency and a receive frequency are entered simultaneously through programming interface (107) and the electro-mechanically tunable duplexer system (100) is configured accordingly.
[0055] In one embodiment, the controller (106) may include one or more processors, electronic circuitry, power amplifier, power driver circuitry for driving SM1 (104) and SM2 (105), a memory for storing the instruction received via programming interface. Further, a programming interface may include USB, display coupled with touch screen, switches, etc. enabling users to provide one or more commands.
[0056] In an exemplary embodiment, figures 3 to 8 illustrate sample testing results of the disclosed electro-mechanically tunable duplexer system (100). Figure 3 illustrates measured transmission response of tunable duplexer with 1dB cross over (C1) between transmit and receive frequency bands. Figure 4 illustrates measured transmission response of the electro-mechanically tunable duplexer system (100) with 3dB cross over (C2) between transmit and receive frequency bands. Figure 5 illustrates measured transmission response of the electro-mechanically tunable duplexer system (100) with 20dB cross over (C1) between transmit and receive frequency bands. Figure 6 illustrates measured transmission response of the electro-mechanically tunable duplexer system (100) with 40dB cross over (C1) between transmit and receive frequency bands. Figure 7 illustrates measured transmission response of the electro-mechanically tunable duplexer system (100) with fixed Tx band and varying Rx bands. Figure 8 illustrates measured transmission response of the electro-mechanically tunable duplexer system (100) with fixed Rx band and varying Tx bands.
[0057] The above illustration of figures 3 to 8 shows that advantageously the designed electro-mechanically duplexer system can efficiently meet the demand of the high-end application, i.e., the demand of closer separation in transmit and receive frequency band, thereby the transmit and the receive frequency bands can be overlapped without degrading the common port matching. A single duplexer can be configured for 4,4 GHz to 5 GHz with high selectivity and can eliminate the fixed duplexers using multiport for configuration of range of frequency with low insertion loss.
[0058] At least some of the technical advantages of the presently disclosed invention include, but are not limited to:
• Single tunning element mechanism for each filter circulator, stepper motor.
• 100 MHz ripple over predetermined range of C band frequencies.
• High transmit and receive isolation i.e., >60 dB can be achieved for transmit and receive frequency band with at least separation of 200 MHz
[0059] A single duplexer can be configured for 4,4 GHz to 5 GHz with high selectivity and can eliminate the fixed duplexers using multiport for configuration of range of frequency with low insertion loss. The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.
,CLAIMS:

1. An electro-mechanically tunable duplexer system (100), the system comprising:
a plurality of tunable bandpass filters (102, 103) configured to be tuned for a predetermined range of frequencies;
a plurality of stepper motors (104, 105) connected to the bandpass filters (102, 103), and configured to tune the filters (102, 103) for the predetermined range of frequencies;
a motor driving and controller unit (106) connected to the stepper motors (104, 105) and configured to drive the stepper motors (104, 105); and
a circulator connected to the filters (102, 103) and an antenna (111), and configured to switch between the plurality of tunable filters (102, 103), to couple the antenna to at least one of the plurality of tunable filters (102, 103).

2. The electro-mechanically tunable duplexer system (100) as claimed in claim 1, wherein the plurality of bandpass filters comprises a first bandpass filter (102) connected to a receiver terminal (108) and second bandpass filter (103) connected to a transmitter terminal (109).

3. The electro-mechanically tunable duplexer system (100) as claimed in claim 1, wherein the plurality of stepper motors comprises a first stepper motor (104) and second stepper motor (105).

4. The electro-mechanically tunable duplexer system (100) as claimed in claims 1 to 3, wherein the first stepper motor (104) is connected to the first bandpass filter (102) and the second stepper motor (105) is connected to the second bandpass filter (103).

5. The electro-mechanically tunable duplexer system (100) as claimed in claims 1 and 2, wherein the circulator is configured to switch between the first bandpass filter (102) and the second bandpass filter (103) for receive and transmit operations respectively.

6. The electro-mechanically tunable duplexer system (100) as claimed in claim 1, wherein the predetermined range of frequencies of the bandpass filters is 4.4 Ghz to 5 Ghz.

7. The electro-mechanically tunable duplexer system (100) as claimed in claim 1, wherein the system further comprises a programming interface (107) to receive user inputs for tuning the bandpass filters for the predetermined range of frequencies.

8. An electro-mechanically tunable bandpass filter (200) comprising:
one or more metallic resonators (206) coaxially mounted on a non-conducting rod (208), each resonator placed inside in a metallic elliptical casing (204), wherein the non-conducting rod (208) is coupled to a stepper motor;
one or more cavity metal probes (203) placed at a front end and a rear end of the elliptical casing (204);
one or more coaxial to stripline transitions (202) connected to the one or more metal cavity probes (203), the one or more coaxial to stripline transitions (202) further connected to a circulator (101) and a terminal of a duplexer (108, 109).

9. The electro-mechanically tunable bandpass filter (200) as claimed in claim 8, wherein each metallic resonator (206) is affixed with at least two linear dual ended loads, each dual ended load being placed at a first end and a second end of the resonator respectively.

10. The electro-mechanically tunable bandpass filter (200) as claimed in claim 8, wherein the metallic elliptical casing (204) includes a coupling window (205) for coupling with an adjacent casing (204).

11. The electro-mechanically tunable bandpass filter (200) as claimed in claim 8, wherein the stepper motor is driven by a motor diving and controller unit to rotate the non-conducting rod (208) about its axis, to thereby rotate the resonator (206) and configure the bandpass filter for a predetermined range of frequencies.

12. The electro-mechanically tunable bandpass filter (200) as claimed in claim 11, wherein a rotation angle of the resonator (206) is 45o about its axis.

13. The electro-mechanically tunable bandpass filter (200) as claimed in claim 11, wherein the predetermined range of frequencies of the bandpass filter is 4.4 GHz to 5 Ghz.