Patent Publication Number: US-10326189-B2

Title: Ortho-mode transducer and diplexer

Description:
TECHNICAL FIELD 
     This disclosure relates to integrated orthogonal-mode transducers and diplexers. 
     BACKGROUND 
     Radio links are widely used for wireless communications between mobile phones and base stations within a communication network. The use of two radio links both operating at a same frequency, but with cross-polarization, can double output capacity of the radio links. To achieve cross polarization, an antenna is coupled to two radios (transmitter and receiver), with one radio transmitting and receiving with a vertical polarization and the other radio transmitting and receiving with a horizontal polarization, and employing an orthogonal-mode transducer to separate the vertically polarized signals from the horizontally polarized signals. 
     SUMMARY 
     Implementing cross polarization at higher bandwidths including the E-band extending between 60 Gigahertz to 80 Gigahertz becomes challenging due to frequency mismatches between the orthogonal-mode transducer and the radios. The present disclosure describes an integrated orthogonal-mode transducer and diplexers that accommodate cross polarization at various bandwidths, inter alia. 
     One aspect of the disclosure provides a method for splitting or combining between a circular polarized signal and vertical and horizontal polarized signals. The method includes receiving, through a vertical polarization port of an orthogonal-mode transducer, a vertical polarized signal from a vertical polarization diplexer and receiving, through a horizontal polarization port of the orthogonal-mode transducer, a horizontal polarized signal from a horizontal polarization diplexer. The method also includes receiving, through a common port of the orthogonal-mode transducer, a circular polarized signal comprising the vertical polarized signal and the horizontal polarized signal and receiving, through a common waveguide connected to the common port and in communication with the vertical polarization port and the horizontal polarization port, the circular polarized signal. The common waveguide includes a septum polarizer configured to split or combine between the circular polarized signal and the vertical polarized signal and the horizontal polarized signal. 
     Implementations of the disclosure may include one or more of the following optional features. In some implementations, the method includes receiving the vertical polarized signal through a vertical polarization waveguide connected to the vertical polarization port. The vertical polarization waveguide may be connected to the common waveguide. The method may also include receiving the horizontal polarized signal through a horizontal polarization waveguide connected to the horizontal polarization port. The horizontal polarization waveguide may be configured to define a first curved path and a second curved path oriented differently from the first curved path. The horizontal polarization waveguide may define a bifurcation into first and second bifurcated waveguides, the first and second bifurcated waveguides connected to the common waveguide. 
     The first curved path of the horizontal polarization waveguide may be disposed in a first plane and the second curved path of the horizontal polarization waveguide may be disposed in a second plane substantially perpendicular to the first plane. Each bifurcated waveguide may define a third curved path disposed in a third plane parallel to the second plane and a fourth curved path disposed in a fourth plane parallel to the first plane. The common waveguide may define a bifurcation junction having a square cross-sectional shape. The bifurcation junction may be connected to the first and second bifurcated waveguides of the horizontal polarization waveguide. The common port of the orthogonal-mode transducer may define a circular cross-sectional shape, and the vertical polarization port and the horizontal polarization port may each define a rectangular cross-sectional shape. 
     In some examples, the vertical polarization diplexer includes: a vertical polarization transmit port; a vertical polarization receive port; and a vertical polarization common port in communication with the vertical polarization transmit port, the vertical polarization receive port, and the vertical polarization port of the orthogonal-mode transducer. The vertical polarization diplexer may also include: a vertical polarization transmit waveguide connected to the vertical polarization transmit port and the vertical polarization common port; a vertical polarization receive waveguide connected to the vertical polarization receive port and the vertical polarization common port; and a vertical polarization common waveguide connected to the vertical polarization common port and the vertical polarization port of the orthogonal-mode transducer. The vertical polarization transmit waveguide, the vertical polarization receive waveguide, and the vertical polarization common waveguide may each define a rectangular cross-sectional shape. The vertical polarization transmit waveguide and the vertical polarization receive waveguide may be configured to receive a corresponding vertical polarized transmit signal and a corresponding vertical polarized receive signal at different frequencies. 
     In some examples, the horizontal polarization diplexer includes: a horizontal polarization transmit port; a horizontal polarization receive port; and a horizontal polarization common port in communication with the horizontal polarization transmit port, the horizontal polarization receive port, and the horizontal polarization port of the orthogonal-mode transducer. The horizontal polarization diplexer may also include: a horizontal polarization transmit waveguide connected to the horizontal polarization transmit port and the horizontal polarization common port; a horizontal polarization receive waveguide connected to the horizontal polarization receive port and the horizontal polarization common port; and a horizontal polarization common waveguide connected to the horizontal polarization common port and the horizontal polarization port of the orthogonal-mode transducer. The horizontal polarization transmit waveguide, the horizontal polarization receive waveguide, and the horizontal polarization common waveguide may each define a rectangular cross-sectional shape. The horizontal polarization transmit waveguide and the horizontal polarization receive waveguide may be configured to receive a corresponding horizontal polarized transmit signal and a corresponding horizontal polarized receive signal at different frequencies. 
     In some implementations, the vertical polarization transmit waveguide is configured to receive the vertical polarized transmit signal having a frequency between about 81 GHz and about 86 GHz. The vertical polarization receive waveguide may be configured to receive the vertical polarized receive signal having a frequency between about 71 GHz and about 76 GHz. The horizontal polarization transmit waveguide may be configured to receive the horizontal polarized transmit signal having a frequency between about 81 GHz and about 86 GHz. The horizontal polarization receive waveguide may be configured to receive the horizontal polarized receive signal having a frequency between about 71 GHz and about 76 GHz. 
     In some examples, the method includes receiving the vertical polarized signal through the vertical polarization diplexer to/from a vertical polarization radio having a vertical polarization transmit output in communication with the vertical polarization transmit port of the vertical polarization diplexer and a vertical polarization receive input in communication with the vertical polarization receive port of the vertical polarization diplexer. The method may also include receiving the horizontal polarized signal through the horizontal polarization diplexer to/from a horizontal polarization radio having a horizontal polarization transmit output in communication with the horizontal polarization transmit port of the horizontal polarization diplexer and a horizontal polarization receive input in communication with the horizontal polarization receive port of the horizontal polarization diplexer. 
     In some examples, the method includes receiving the vertical polarized transmit signal through a vertical polarization powered amplifier connected to the vertical polarization transmit output of the vertical polarization radio and the vertical polarization transmit port of the vertical polarization diplexer and receiving the vertical polarized receive signal through a vertical polarization low noise amplifier connected to the vertical polarization receive input of the vertical polarization radio and the vertical polarization receive port of the vertical polarization diplexer. The method may also include receiving the horizontal polarized transmit signal through a horizontal polarization powered amplifier connected to the horizontal polarization transmit output of the horizontal polarization radio and the horizontal polarization transmit port of the horizontal polarization diplexer and receiving the horizontal polarized receive signal through a horizontal polarization low noise amplifier connected to the horizontal polarization receive input of the horizontal polarization radio and the horizontal polarization receive port of the horizontal polarization diplexer. 
     Another aspect of the disclosure provides a system for splitting or combining between a circular polarized signal and vertical and horizontal polarized signals. The system includes an orthogonal-mode transducer having a vertical polarization port, a horizontal polarization port, and a common port. The common port is in communication with the vertical polarization port and the horizontal polarization port and is configured to communicate with an antenna. The system also includes a vertical polarization diplexer having a vertical polarization transmit port, a vertical polarization receive port, and a vertical polarization common port. The vertical polarization common port is in communication with the vertical polarization port of the orthogonal-mode transducer. The system further includes a horizontal polarization diplexer having a horizontal polarization transmit port, a horizontal polarization receive port, and a horizontal polarization common port. The horizontal polarization common port is in communication with the horizontal polarization port of the orthogonal-mode transducer. The orthogonal-mode transducer includes a septum polarizer connected to the common port and is in communication with the vertical polarization port and the horizontal polarization port. The septum polarizer is configured to split or combine between: a circular polarized signal received through the common port; and a vertical polarized signal received through the vertical polarization port and a horizontal polarized signal received through the horizontal polarization port. 
     This aspect may include one or more of the following optional features. In some implementations, the orthogonal-mode transducer includes a vertical polarization waveguide connected to the vertical polarization port and a horizontal polarization waveguide connected to the horizontal polarization port. The horizontal polarization waveguide may be configured to define a first curved path and a second curved path oriented differently from the first curved path. The horizontal polarization waveguide may define a bifurcation into first and second bifurcated waveguides. The orthogonal-mode transducer may also include a common waveguide connected to the common port, the vertical polarization waveguide, and the first and second bifurcated waveguides of the horizontal polarization waveguide. The first curved path of the horizontal polarization waveguide may be disposed in a first plane and the second curved path of the horizontal polarization waveguide may be disposed in a second plane substantially perpendicular to the first plane. 
     Each bifurcated waveguide may define a third curved path disposed in a third plane parallel to the second plane and a fourth curved path disposed in a fourth plane parallel to the first plane. The common waveguide may define a bifurcation junction having a square cross-sectional shape. The bifurcation junction may be connected to the first and second bifurcated waveguides of the horizontal polarization waveguide. The common port of the orthogonal-mode transducer may define a circular cross-sectional shape, and the vertical polarization port and the horizontal polarization port may each define a rectangular cross-sectional shape. 
     In some implementations, the vertical polarization diplexer includes: a vertical polarization transmit waveguide connected to the vertical polarization transmit port and the vertical polarization common port; a vertical polarization receive waveguide connected to the vertical polarization receive port and the vertical polarization common port; and a vertical polarization common waveguide connected to the vertical polarization common port and the vertical polarization port of the orthogonal-mode transducer. The vertical polarization transmit waveguide, the vertical polarization receive waveguide, and the vertical polarization common waveguide may each define a rectangular cross-sectional shape. The vertical polarization transmit waveguide and the vertical polarization receive waveguide may be configured to receive a corresponding vertical polarized transmit signal and a corresponding vertical polarized receive signal at different frequencies. 
     In some examples, the horizontal polarization diplexer includes: a horizontal polarization transmit waveguide connected to the horizontal polarization transmit port and the horizontal polarization common port; a horizontal polarization receive waveguide connected to the horizontal polarization receive port and the horizontal polarization common port; and a horizontal polarization common waveguide connected to the horizontal polarization common port and the horizontal polarization port of the orthogonal-mode transducer. The horizontal polarization transmit waveguide, the horizontal polarization receive waveguide, and the horizontal polarization common waveguide may each define a rectangular cross-sectional shape. The horizontal polarization transmit waveguide and the horizontal polarization receive waveguide may be configured to receive a corresponding horizontal polarized transmit signal and a corresponding horizontal polarized receive signal at different frequencies. 
     In some examples, the vertical polarization transmit waveguide is configured to receive the vertical polarized transmit signal having a frequency between about 81 GHz and about 86 GHz. The vertical polarization receive waveguide may be configured to receive the vertical polarized receive signal having a frequency between about 71 GHz and about 76 GHz. The horizontal polarization transmit waveguide may be configured to receive the horizontal polarized transmit signal having a frequency between about 81 GHz and about 86 GHz. The horizontal polarization receive waveguide may be configured to receive the horizontal polarized receive signal having a frequency between about 71 GHz and about 76 GHz. 
     The system may include a vertical polarization radio having a vertical polarization transmit output in communication with the vertical polarization transmit port of the vertical polarization diplexer and a vertical polarization receive input in communication with the vertical polarization receive port of the vertical polarization diplexer. The system may also include a horizontal polarization radio having a horizontal polarization transmit output in communication with the horizontal polarization transmit port of the horizontal polarization diplexer and a horizontal polarization receive input in communication with the horizontal polarization receive port of the horizontal polarization diplexer. 
     In some examples, a vertical polarization powered amplifier (PA) is connected to the vertical polarization transmit output of the vertical polarization radio and the vertical polarization transmit port of the vertical polarization diplexer. The system may include a vertical polarization low noise amplifier (LNA) connected to the vertical polarization receive input of the vertical polarization radio and the vertical polarization receive port of the vertical polarization diplexer. In some examples, a horizontal polarization powered amplifier is connected to the horizontal polarization transmit output of the horizontal polarization radio and the horizontal polarization transmit port of the horizontal polarization diplexer. The system may also include a horizontal polarization low noise amplifier connected to the horizontal polarization receive input of the horizontal polarization radio and the horizontal polarization receive port of the horizontal polarization diplexer. 
     The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view of example vertical and horizontal polarization radios each in communication with an example integrated orthogonal-mode transducer-diplexer (OMT-diplexer). 
         FIGS. 2A-2C  are schematic views of the integrated OMT-diplexer of  FIG. 1 . 
         FIG. 2D  is a schematic view of a double bended horizontal polarization waveguide of the integrated OMT-diplexer of  FIGS. 2A-2C . 
         FIG. 2E  is a schematic view of a common waveguide of the integrated OMT-diplexer of  FIG. 1 . 
         FIG 2F  is a perspective view of an example OMT-diplexer. 
         FIG. 3  is a plot showing example insertion loss through the integrated OMT-diplexer of  FIG. 1 . 
         FIG. 4  is a plot showing example cross polarization through the integrated OMT-diplexer of  FIG. 1 . 
         FIG. 5  is an example arrangement of operations for a method of splitting or combining between a circular polarized signal received through a common port of an orthogonal-mode transducer, and a vertical polarized signal and a horizontal polarized signal. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , in some implementations, a system  100  includes a vertical polarized radio  102  and a horizontal polarized radio  104  configured to communicate with an antenna  190  through an integrated unit  200  that includes a vertical polarization diplexer  210 , a horizontal polarization diplexer  230 , and an orthogonal-mode transducer (OMT)  250 . The OMT  250  may also be referred to as an ortho-mode transducer. The vertical polarized radio  102  is configured to transmit/receive vertical polarized signals  20 ,  20   t ,  20   r  to/from the OMT  250  through the vertical polarization diplexer  210 , and the horizontal polarized radio  104  is configured to transmit/receive horizontal polarized signals  40 ,  40   t ,  40   r  to/from the OMT  250  through the horizontal polarization diplexer  230 . The integrated unit  200  may be interchangeably referred to as an integrated OMT-diplexer  200 . 
     In the example shown, the vertical polarization diplexer  210  includes a vertical polarization common port  220  that communicates with a vertical polarization port  252  of the OMT  250 , and the horizontal polarization diplexer  230  includes a horizontal polarization common port  240  that communicates with a horizontal polarization port  256  of the OMT  250 . In some examples, the OMT  250  combines a vertical polarized transmit signal  20 ,  20   t  from the vertical polarized radio  102  and a horizontal polarized transmit signal  40 ,  40   t  from the horizontal polarized radio  104  into a circular polarized signal  50  for transmission through the antenna  190 . In other examples, the OMT  250  receives the circular polarized signal  50  through the antenna  190  and splits the circular polarized signal  50  into a vertical polarized receive signal  20 ,  20   r  and a horizontal polarized receive signal  40 ,  40   r . The OMT  250  may direct the vertical polarized receive signal  20   r  to the vertical polarized radio  102  through the vertical polarization diplexer  210  and the horizontal polarized receive signal  40   r  to the horizontal polarized radio  104  through the horizontal polarization diplexer  230 . 
     The vertical polarization radio  102  has a vertical polarization transmit output  112  in communication with a vertical polarization transmit port  212  of the vertical polarization diplexer  210  for transmitting the vertical polarized transmit signal  20   t  to the vertical polarization diplexer  210 . In some implementations, a vertical polarization powered amplifier (PA)  122  connected to the vertical polarization transmit output  112  and the vertical polarization transmit port  212  amplifies the vertical polarized transmit signal  20   t  before the vertical polarization transmit port  212  of the vertical polarization diplexer  210  receives the vertical polarized transmit signal  20   t . Additionally, the vertical polarization radio  102  has a vertical polarization receive input  114  in communication with a vertical polarization receive port  214  of the vertical polarization diplexer  210  for receiving the vertical polarized receive signal  20   r  from the vertical polarization diplexer  210 . In some implementations, a vertical polarization low-noise amplifier (LNA)  124  connected to the vertical polarization receive port  214  amplifies the vertical polarized receive signal  20   r.    
     Still referring to  FIG. 1 , the horizontal polarization radio  104  has a horizontal polarization transmit output  132  in communication with a horizontal polarization transmit port  232  of the horizontal polarization diplexer  230  for transmitting the horizontal polarized transmit signal  40   t  to the horizontal polarization diplexer  230 . In some implementations, a horizontal polarization PA  142  connected to the horizontal polarization transmit output  132  and the horizontal polarization transmit port  232  amplifies the horizontal polarized transmit signal  40   t  before the horizontal polarization transmit port  232  of the horizontal polarization diplexer  230  receives the horizontal polarized transmit signal  40   t . Additionally, the horizontal polarization radio  104  has a horizontal polarization receive input  134  in communication with a horizontal polarization receive port  234  of the horizontal polarization diplexer  230  for receiving the horizontal polarized receive signal  40   r  from the horizontal polarization diplexer  230 . In some implementations, a horizontal LNA  144  connected to the horizontal polarization receive port  234  amplifies the horizontal polarized receive signal  40   r.    
     The vertical and horizontal polarized radios  102 ,  104  each includes transmit circuitry including a digital transmit signal input configured to receive in-phase (I) data (I) and quadrature (Q) data and a digital-to-analog converter(s) (DAC) configured to convert the I/Q data from the digital domain to the analog domain. The transmit circuitry further includes a modulator in communication with the DAC and configured to modulate the analog I/Q data into an analog transmit signal  20   t ,  40   t  for transmission out the corresponding transmit output  112 ,  132 . 
     The vertical and horizontal polarized radios  102 ,  104  also include receive circuitry including the corresponding receive input  114 ,  134  configured to receive an analog receive signal  20   r ,  40   r  and a demodulator in communication with the receive input  114 ,  134 . The demodulator is configured to demodulate the analog receive signal  20   r ,  40   r  into corresponding analog I/Q data. The receive circuitry further includes an analog-to-digital converter(s) (ADC) configured to convert the analog I/Q data from the analog domain to the digital domain. An analog receive signal output in communication with the ADC may output the digital I/Q data. 
       FIGS. 2A-2E  provide schematic views of the integrated OMT-diplexer  200  of  FIG. 1 .  FIGS. 2A and 2B  show a housing  202  defining various enclosed ports and waveguides configured to direct the vertical and horizontal polarized signals  20 ,  40  between the antenna  190  and the corresponding vertical polarized radio  102  or the horizontal polarized radio  104 .  FIG. 2C  shows the housing  202  removed for clarity. 
     In some implementations, the OMT  250  includes a vertical polarization waveguide  254  connected to the vertical polarization port  252 , a horizontal polarization waveguide  258  connected to the horizontal polarization port  256 , and a common port  260  connected to a common waveguide  262  and configured to communicate with the antenna  190 . The common waveguide  262  connects to each of the vertical polarization waveguide  254  and the horizontal polarization waveguide  258  to provide communication between the common port  260  and each of the vertical polarization port  252  and the horizontal polarization port  256 . For instance, the vertical polarization waveguide  254  is configured to direct the vertical polarized transmit signal  20   t  received through the vertical polarized port  252  from the vertical polarization diplexer  210  to the common waveguide  262 , and direct the vertical polarized received signal  20   r  received from the common waveguide  262  to the vertical polarized port  252 . Similarly, the horizontal polarization waveguide  258  is configured to direct the horizontal polarized transmit signal  40   t  received through the horizontal polarized port  256  from the horizontal polarization diplexer  230  to the common waveguide  262 , and direct the horizontal polarized received signal  40   r  received from the common waveguide  262  to the horizontal polarized port  256 . In some examples, the vertical polarization waveguide  254  is substantially straight and the horizontal polarization waveguide  258  includes multiple bends. 
     In the examples shown, the common waveguide  262  of the OMT  250  includes a septum polarizer  264  configured to split or combine between: (1) the circular polarized signal  50  received through the common port  260 ; and (2) the vertical polarized signal  20  and the horizontal polarized signal  40 . In some examples, the septum polarizer  264  splits the circular polarized signal  50  received through the common port  260  from the antenna  190  into the vertical polarized receive signal  20   r  and the horizontal polarized receive signal  40   r . In other examples, the septum polarizer  264  combines the vertical polarized transmit signal  20   t  received through the vertical polarization port  252  and the horizontal polarized transmit signal  40   t  received through the horizontal polarization port  256  into the circular polarized signal  50  prior to transmission through the antenna  190 . The septum polarizer  264  may obtain an insertion loss at the input ports  212 ,  214 ,  232 ,  234  of less than one (1.0) decibels (dB) with return losses exceeding eighteen (18) dB. Moreover, the septum polarizer  264  of the integrated OMT-diplexer  200  may achieve cross-polarization power levels that exceed sixty-five (65) dB and isolation exceeding seventy-five (75) dB. 
     Referring to the vertical polarization diplexer  210 , the vertical polarization transmit port  212  connects to a vertical polarization transmit waveguide  216  at a first end, the vertical polarization receive port  214  connects to a vertical polarization receive waveguide  218  at a second end, and a vertical polarization common port  220  connects to a corresponding second end of each of the vertical polarization transmit waveguide  216  and the vertical polarization receive waveguide  218 . In some implementations, a vertical polarization common waveguide  222  connects the vertical polarization common port  220  to the vertical polarization port  252  of the OMT  250  to thereby place the vertical polarization common port  220  in communication with the vertical polarization transmit port  212 , the vertical polarization receive port  214 , and the vertical polarization port  252  of the OMT  250 . 
     The vertical polarization transmit waveguide  216  is configured to receive the vertical polarized transmit signal  20   t  from the vertical polarized radio  102  via the vertical polarization transmit port  212 . The vertical polarization receive waveguide  218  is configured to receive the vertical polarized receive signal  20   r  from the OMT  250  via the vertical polarization common port  220 . In some examples, the vertical polarization transmit waveguide  216  and the vertical polarization receive waveguide  218  receive the corresponding vertical polarized transmit signal  20   t  and the corresponding vertical polarized receive signal  20   r  at different frequencies. In one example, the vertical polarization transmit waveguide  216  is configured to receive the vertical polarized transmit signal  20   t  having a frequency between about 81 Gigahertz (GHz) and about 86 GHz, and the vertical polarization receive waveguide  218  is configured to receive the vertical polarized receive signal  20   r  having a frequency between about 71 GHz and about 76 GHz. Accordingly, the vertical polarization transmit waveguide  216  may correspond to a high-band frequency of the vertical polarization diplexer  210  and the vertical polarization receive waveguide  218  may correspond to a low-band frequency of the vertical polarization diplexer  210 . 
     As shown in  FIG. 2B , the vertical polarization transmit waveguide  216  and the vertical polarization receive waveguide  218  may each have a corresponding band pass filter (BPF)  217 ,  219 , and the horizontal polarization common port  240  may include a septum  241 . In some configurations, the vertical polarization transmit waveguide  216  implements a 10 th  order Chebyshev BPF  217  using an inductive iris technique and the vertical horizontal polarization transmit waveguide  218  implements a 9 th  order Chebyshev BPF  219  using the inductive iris technique. However, one or both of the waveguides  216 ,  218  may use capacitive filters in other configurations. The order of the BPFs  217 ,  219  may be based on the specified rejection. The vertical polarization transmit waveguide  216 , the vertical polarization receive waveguide  218 , and the vertical polarization common waveguide  222  may each define a rectangular cross-sectional shape. 
     Referring now to the horizontal polarization diplexer  230 , the horizontal polarization transmit port  232  connects to a horizontal polarization transmit waveguide  236  at a first end, the horizontal polarization receive port  234  connects to a horizontal polarization receive waveguide  238  at a second end, and a horizontal polarization common port  240  connects to a corresponding second end of each of the horizontal polarization transmit waveguide  236  and the horizontal polarization receive waveguide  238 . In some implementations, a horizontal polarization common waveguide  242  connects the horizontal polarization common port  240  to the horizontal polarization port  256  of the OMT  250  to thereby place the horizontal polarization common port  240  in communication with the horizontal polarization transmit port  232 , the horizontal polarization receive port  234 , and the horizontal polarization port  256  of the OMT  250 . 
     The horizontal polarization transmit waveguide  236  is configured to receive the horizontal polarized transmit signal  40   t  from the horizontal polarized radio  104  via the horizontal polarization transmit port  232 . The horizontal polarization receive waveguide  238  is configured to receive the horizontal polarized receive signal  40   r  from the OMT  250  via the horizontal polarization common port  240 . In some examples, the horizontal polarization transmit waveguide  236  and the horizontal polarization receive waveguide  238  receive the corresponding horizontal polarized transmit signal  40   t  and the corresponding horizontal polarized receive signal  40   r  at different frequencies. In one example, the horizontal polarization transmit waveguide  236  is configured to receive the horizontal polarized transmit signal  40   t  having a frequency between about 81 GHz and about 86 GHz, and the horizontal polarization receive waveguide  238  is configured to receive the horizontal polarized receive signal  40   r  having a frequency between about 71 GHz and about 76 GHz. Accordingly, the horizontal polarization transmit waveguide  236  may correspond to a high-band frequency of the horizontal polarization diplexer  230  and the horizontal polarization receive waveguide  238  may correspond to a low-band frequency of the horizontal polarization diplexer  230 . 
     As shown in  FIG. 2B , the horizontal polarization transmit waveguide  236  and the horizontal polarization receive waveguide  238  may each have a corresponding band pass filter (BPF)  237 ,  239 , and the horizontal polarization common port  240  may include a septum  241 . In some configurations, the horizontal polarization transmit waveguide  236  implements a 10 th  order Chebyshev BPF  237  using an inductive iris technique and the horizontal polarization transmit waveguide  238  implements a 9 th  order Chebyshev BPF  239  using the inductive iris technique. However, one or both of the waveguides  236 ,  238  may use capacitive filters in other configurations. The order of the BPFs  237 ,  239  may be based on the specified rejection. The horizontal polarization transmit waveguide  236 , the horizontal polarization receive waveguide  238 , and the horizontal polarization common waveguide  242  may each define a rectangular cross-sectional shape. 
     In the examples shown, the vertical polarization waveguide  254  of the OMT  250  is substantially straight and extends between the vertical polarization port  252  and the common waveguide  262 . The vertical polarization waveguide  254  is configured to receive the vertical polarized signal  20  that may include the vertical polarized transmit signal  20   t  and/or the vertical polarized receive signal  20   r . For instance, the vertical polarized transmit signal  20   t  may travel through the vertical polarized waveguide  254  in a direction from the vertical polarization port  252  to the common waveguide  262 . On the other hand, the vertical polarized receive signal  20   r  may travel through the vertical polarized waveguide  254  in an opposite direction from the common waveguide  262  to the vertical polarization port  252 . 
     Whereas the vertical polarization waveguide  254  may be substantially straight, the horizontal polarization waveguide  258  may include a double bend waveguide. The double bend horizontal polarization waveguide  258  is configured to receive the horizontal polarized signal  40  that may include the horizontal polarized transmit signal  40   t  and/or the horizontal polarized receive signal  40   r . For instance, the horizontal polarized transmit signal  40   t  may travel through the horizontal polarized waveguide  258  in a direction from the horizontal polarization port  256  to the common waveguide  262 . On the other hand, the horizontal polarized receive signal  40   r  may travel through the horizontal polarized waveguide  258  in an opposite direction from the common waveguide  262  to the horizontal polarization port  256 . 
     Referring to  FIG. 2C , in some implementations, the horizontal polarization waveguide  258  defines a first curved path  258   a  and a second curved path  258   b  oriented differently than the first curved path  258   a . In the example shown, the first curved path  258   a  is disposed in a first plane  270  and the second curved path  258   b  is disposed in a second plane  272  substantially perpendicular to the first plane  270 . In the example shown, the first plane  270  is coplanar with the a-b plane and the second plane  272  is coplanar with the a-c plane.  FIG. 2D  shows the first and second curved paths  258   a ,  258   b  of the horizontal polarization waveguide  258  disposed in the corresponding first and second planes  270 ,  272  substantially perpendicular to one another. As the horizontal polarization waveguide  258  defines a rectangular cross-sectional shape that rotates 90-degrees between the first curved path  258   a  and the second curved path  258   b , the first curved path  258   a  defines a first width W 1  and the second curved path defines a second width W 2  that is less than the first width W 1 . 
     Referring back to  FIG. 2C , the horizontal polarization waveguide  258  further defines a bifurcation  257  into first and second bifurcated waveguides  259  each connected to the common waveguide  262 . In the example shown, each bifurcated waveguide  259  defines a third curved path  258   c  disposed in a third plane  274  parallel to the second plane  272  and a fourth curved path  258   d  disposed in a fourth plane  276  parallel to the first plane  270 . The third curved path  258   c  may define a third width W 3  that is substantially half of the second width W 2  ( FIG. 2D ), while the fourth curved path  258   d  rotates 90-degrees from the third curved path  258   c  to define the first width W 1 . Accordingly, the fourth curved path  258   d  defined by each of the bifurcated waveguides  259  converts the horizontal polarization waveguide  258  back to the same orientation as the horizontal polarization port  256  before connecting to the common waveguide  262 . In some implementations, the bifurcation  257  power splits the horizontal polarized transmit signal  40   t  into two split signals each directed to the common waveguide  262  along the corresponding first or second bifurcated waveguide  259 . For instance, each of the horizontal polarized transmit signals  40   t  power split by the bifurcation  257  travel along the third and fourth curved paths  258   c ,  258   d  of the corresponding bifurcated waveguide  259  and then combine within the common waveguide  262 . 
       FIG. 2E  shows the common waveguide  262  of the OMT  250  defining a bifurcation junction  280  (e.g., T-junction) connecting each of the bifurcation waveguides  259  to the common waveguide  262 . The bifurcation junction  280  defines a square cross-sectional shape, while each of the bifurcation waveguides  259  define the rectangular cross-sectional shape. Accordingly, the horizontal polarized transmit signals  40   t  recombine within the common waveguide  262  defining the square cross-sectional shape. Moreover, an E-Plane bend  282  is configured to connect the vertical polarization waveguide  254  defining the rectangular cross-sectional shape to the common waveguide  262  defining the square cross-sectional shape. Thereafter, the septum polarizer  264  combines the vertical polarized transmit signal  20   t  received through the vertical polarization waveguide  254  and the horizontal polarized transmit signals  40   t  received through the bifurcation waveguides  259  into the circular polarized signal  50 . The circular polarized signal travels through the common port  260  for transmission from the antenna  190  ( FIG. 1 ). 
     Referring to  FIG. 2F , in some implementations, the housing  202  ( FIGS. 2A and 2B ) of the integrated OMT-diplexer  200  is formed by a base plate  600  and a plurality of upper plates  602 ,  602   a - e  each securing to the base plate  600 . For instance, fasteners  604  may extend through corresponding holes  606  formed through the upper plates  602  and the base plate  600  to secure each upper plate  602  to the base plate  600 . The fasteners  604  may include pins or screws. In some examples, the holes  606  are threaded and adapted to threadably engage with threaded screws  604 . Other fastening techniques may be employed to secure the upper plates  602  to the base plate  600 . 
     Various grooves and channels are formed through opposing surfaces of the upper plates  602  and the base plate  600  to form the ports and waveguides for directing the vertical and horizontal polarized signals  20 ,  40  between the radios  102 ,  104  and the antenna  190 . For instance, the upper plate  602   a  and the base plate  600  may cooperate to define the vertical polarized transmit waveguide  216 , the vertical polarized receive waveguide  218 , and the vertical polarization common waveguide  222  of the vertical polarization diplexer  210 , as well as the vertical polarization waveguide  254  of the OMT  250 . In some examples, the base plate  600  and the upper plates  602  are formed from one or more conductive materials. For instance, the base plate  600  and the upper plates  602  may be formed from 6061 Aluminum. Moreover, the channels forming the ports and waveguides may be lined/coated with a chemical film. 
       FIG. 3  illustrates a plot  300  depicting insertion loss through the integrated OMT-diplexer  200  between the vertical polarization transmit signal  20   t , the vertical polarization receive signal  20   r , the horizontal polarization transmit signal  40   t , and the horizontal polarization receive signal  40   r . The x-axis depicts frequency in Gigahertz (GHz) and the y-axis depicts insertion loss or loss of signal power in decibels (dB). Profile line  302  corresponds to the insertion loss of the vertical polarization receive signal  20   r , profile line  304  corresponds to the insertion loss of the vertical polarization transmit signal  20   t , profile line  306  corresponds to the insertion loss of the horizontal polarization receive signal  40   r , and profile line  308  corresponds to the insertion loss of the horizontal polarization transmit signal  20   t . Between frequencies 71.00 GHz and 76.00 GHz, the vertical polarization receive signal  20   r  received through the vertical polarization receive waveguide  218  and the horizontal polarization receive signal  40   r  received through the horizontal polarization receive waveguide  238  each include insertion value losses equal to values less than 1.0 dB. Additionally, between frequencies 81.00 GHz and 86.00 GHz, the vertical polarization transmit signal  20   t  received through the vertical polarization transmit waveguide  216  and the horizontal polarization transmit signal  40   t  received through the horizontal polarization transmit waveguide  236  each include insertion value losses equal to values less than 1.0 dB. 
       FIG. 4  illustrates a plot  400  depicting cross polarization through the integrated OMT-diplexer  200 . The x-axis depicts frequency in Gigahertz (GHz) and the y-axis depicts signal power in decibels (dB). Thus, cross polarization is specified as the signal power in negative dB, indicating how many decibels the cross polarization is below a desired polarization associated with the orthogonal polarization. Profile line  402  corresponds to the signal power of the vertical polarization receive signal  20   r , profile line  404  corresponds to the signal power of the vertical polarization transmit signal  20   t , profile line  406  corresponds to the signal power of the horizontal polarization receive signal  40   r , and profile line  408  corresponds to the signal power of the horizontal polarization transmit signal  20   t . Between frequencies 71.00 GHz and 76.00 GHz, the vertical polarization transmit and receive signals  20   t ,  20   r  include a cross polarization of greater than 65 dB (i.e., less than negative 65 dB). Also, between frequencies 81.00 GHz and 86.00 GHz, the horizontal polarization transmit and receive signals  40   t ,  40   r  include a cross polarization of greater than 65 dB (i.e., less than negative 65 dB). 
       FIG. 5  is a flow chart of an example method  500  of splitting or combining between a circular polarized signal  50  received through a common port  260  of an orthogonal-mode transducer (OMT)  250 , and a vertical polarized signal  20  and a horizontal polarized signal  40 . At block  502 , the method  500  includes receiving, through a vertical polarization port  252  of an ortho-mode transducer  250 , a vertical polarized signal  20  from a vertical polarization diplexer  210 . At block  504 , the method  500  includes receiving, through a horizontal polarization port  256  of the ortho-mode transducer  250 , a horizontal polarized signal  40  from a horizontal polarization diplexer  230 . At block  506 , the method  500  includes receiving, through a common port  260  of the orthogonal-mode transducer  250 , a circular polarized signal  50  that includes the vertical polarized signal  20  and the horizontal polarized signal  40 . At block  508 , the method  500  includes receiving, through a common waveguide  262  connected to the common port  260  and in communication with the vertical polarization port  252  and the horizontal polarization port  256 , the circular polarized signal  50 . The common waveguide  262  includes a septum polarizer  264  configured to split or combine between the circular polarized signal  50  and the vertical polarized signal  20  and the horizontal polarized signal  40 . 
     A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.