JPH0795644B2 - Multiplexing system for multiple electromagnetic signal channels - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave multiplexer operated by a plurality of electromagnetic signal channels, and more particularly to signals of different frequencies in a first set of signal channels and different frequencies of a second set of signal channels. Regarding signal multiplexing. Prior to combining the two sets of signals, the first channel signal is circularly polarized and the second channel signal is linearly polarized.

[0002]

Microwave multiplexers are used in communication systems, such as communication satellite systems, to combine multiple signal channels for transmission along a common transmission line, such as an antenna feed. In a frequently used form of communication satellite system, an antenna mounted on a satellite transmits and receives electromagnetic signals that propagate between the satellite and an antenna located on the surface of the ground. Multiple signal channels separated by frequency and / or polarization are communicated by two antennas. The signals of all channels, which are either linearly polarized or circularly polarized, propagate in the same direction along the same transmission line, so all signals transmitted by the transmitting antenna reach the receiving antenna. It is important to.

[0003]

Although multiplex systems are used in both land and communication satellite systems, the complications of mechanical complexity due to the undesired heavy construction entail problems. Currently, there is a need for a multiplexing system suitable for satellite and land-based communication systems that is mechanically simple and has reduced mass.

[0004]

SUMMARY OF THE INVENTION The above problems are addressed by a multiplexing system that combines a plurality of electromagnetic signals for propagation along a common transmission line, preferably a square waveguide, connectable to an antenna feed horn of square cross section. Is overcome and other advantages are given. Such a feed horn can support both circularly polarized and linearly polarized electromagnetic waves. The square waveguide has opposite top and bottom walls and opposite side walls. Since the feed horn is common to both circularly polarized and linearly polarized electromagnetic waves, the antenna reflector illuminated by the feed horn gives the same direction of radiation of the signal in both polarizations.

The system is operated on multiple sets of signal channels, including a first set of A channel signals and a second set of B channel signals. The system includes a square waveguide as described above having a first end and a second end opposite the first end and an input port and an output port connected to the first end of the waveguide. And a circular polarizer having. All A channel signals are fed to the input port of the polariser. The frequencies of the A channel signals are different from each other, and so is the B channel signal. All A channel signal frequencies and B channel signal frequencies are within the passband of the waveguide, and all A channel signals pass through the polarizer and along the waveguide to the second end of the waveguide. Propagate.

The B channel signal is coupled into the square waveguide by a plurality of coupling means arranged in series along the waveguide. Each coupling means operates at a different frequency of the B channel frequency that selectively couples the B channel signal to the square waveguide for propagation in the direction of the second end of the waveguide.

Each coupling means comprises a rectangular waveguide having a pair of opposite narrow walls and a pair of opposite wide walls and having an input port for receiving a B channel signal. Further included within the coupling means is a filter assembly including a plurality of cylindrical cavity filters connecting the wide walls of the rectangular waveguide and the walls of the square waveguide. The B-channel signal is coupled from the rectangular waveguide to the square waveguide by the filter assembly. Further, the filter assembly directionally couples the B channel signal to the square waveguide for propagating in the direction of the second end of the square waveguide, and an interface between the filter assembly and the square waveguide. Has a plurality of slot holes arranged in.

In a first embodiment of the invention, the filter assembly of the coupling means comprises a first and a second filter. The two waveguides are located in parallel. The first filter is connected between the wide wall of the rectangular waveguide and the side wall of the square waveguide. The second filter is connected between the side wall of the rectangular waveguide and the bottom wall of the square waveguide. The interface between the end of the first filter and the rectangular waveguide and the interface between the second end and the square waveguide are respectively rectangular waveguides for coupling electromagnetic power therethrough. A laterally extending first slot end hole and a laterally extending square waveguide second slot end hole. The interface between the side of the first filter and the square waveguide and the second
The interface between the sides of the filter and the rectangular waveguide is a first slot side hole and a rectangle extending respectively parallel to the long axis of the square waveguide for coupling electromagnetic power therethrough. A second slot side hole extends parallel to the long axis of the waveguide.

In a second embodiment of the present invention, the coupling means filter assembly also comprises first and second filters. However, the two waveguides are positioned vertically at the location of the coupling means. The first filter connects between the rectangular wide wall and the sidewall of the square waveguide. The second filter is connected between the narrow wall of the rectangular waveguide and the upper wall of the square waveguide. The interface between the side of the first filter and the wide wall of the rectangular waveguide and the interface between the side of the second filter and the narrow wall of the rectangular waveguide pass through them. Each of the rectangular waveguides has a first slot side hole extending laterally and a second slot side hole extending parallel to the long axis of the rectangular waveguide for coupling electromagnetic power. . An end of the first filter and a square transverse to the square waveguide and a first slot end hole extending respectively parallel to the long axis of the square waveguide for coupling electromagnetic power therethrough. Second extending
Slot end holes.

[0010]

DETAILED DESCRIPTION FIG. 1 shows a multiplexing system 10 constructed in accordance with the present invention. Multiplexing system 10 is used as part of a communication system 12 that uses satellites 14 to communicate with stations (not shown) on the ground. Multiplexing system 10
While useful in many forms of communication systems and signal processing systems, mechanical simplicity and multiplexing systems 10
Is capable of outputting both linearly polarized waves and circularly polarized electromagnetic waves along the single transmission line 16, which is particularly effective for a communication satellite system. In the case of communication satellite system 12, transmission line 16 couples the multiplexed signal to feed horn 18 which illuminates reflector 20 of antenna 22. Only one piece of reflector 20 is shown for clarity of the drawing. The feed horn 18 has a square shaped aperture hole suitable for emitting both linearly and circularly polarized waves from the common focus of the antenna 22. If desired, holes of circular cross section (not shown) can be used with the transition of the waveguide from a square cross section to a circular cross section to illuminate the reflector 20.

The communication system 12 is generally used for communication satellites, that is, fixed satellite services (FSS) in which signals are emitted as linearly polarized waves, and broadcasting satellite services (BSS) in which signals are emitted as circularly polarized waves 2. It is operated by two forms of communication signals. It should be understood that the FSS and BSS signals are given as examples and that the multiplexing system 10 is generally operated with a first input signal channel A and a second input signal channel B. Each channel contains multiple signals that are offset from each other in the frequency spectrum by using different carrier frequencies.
For example, three carrier frequencies are shown for each channel. In channel A, the three frequencies are F1 and F
2, F3, while in channel B the carrier frequencies are shown as Fa, Fb, Fc.

In the case of communications satellites, the signal is transmitted from the ground station to the satellite 14 for amplification by well-known amplification means (not shown) typically mounted on the satellite 14 and then to the ground. Send again and return. The amplified signal is generated by signal source 24 for the A channel signal and signal source 26 for the B channel signal as shown in FIG. For example, although three sources 24 and three sources 26 are shown, it should be understood that a greater number of sources will typically be provided for each channel. The signals of signal source 24 are combined by multiplexer 28 and provided to the A channel. Source 26
Signals are provided as a group 30 of separate signal transmission lines and, in the preferred embodiment of the invention, three waveguides 34
A, 34B, 34C are configured as a set of rectangular waveguides 34 shown by way of example. Therefore, each channel has multiple signals at different frequencies.

The multiplexing system 10 comprises a square waveguide 32 having a square cross section, a set of rectangular waveguides 34 having a rectangular cross section, a circular polarizer 36 for introducing circular polarization into electromagnetic waves,
A circular polarized wave which is perpendicular to the polarized wave of the polarized wave 36, a circular polarized wave 38 which introduces an electromagnetic wave, and a plurality of couplers 40 are provided. A combiner 40 is provided for the B channel signal frequency which is tuned to a particular frequency of the B channel signal. Coupler 40 is further identified by the references Fa, Fb, Fc and is coupled to waveguides 34A, 34B, 34C, respectively. In the square waveguide 32, four side walls 42 of equal width are provided. Each rectangular waveguide 34 is provided with a top wall 44 and a bottom wall 46 of equal width, and two opposing narrow walls 48 of equal width. Typically, the width of the top wall 44 is twice the width of the narrow wall 48.

In operation of the multiplexing system 10, the signal source
The signal input from 26 to the rectangular waveguide 34 is
It is linearly polarized by an electric field parallel to the narrow wall 48 of 34. The signal output by the multiplexer 28 is also linearly polarized when supplied to the input port of the polarizer 36, and converted by the polarizer 36 into a circularly polarized wave input to the square waveguide 32. The signal input to the rectangular waveguide 34 is the signal source
Propagate from the first end to the other end of each rectangular waveguide 34 coupled to 26. The other end of each rectangular waveguide 34 is matched to the impedance of the rectangular waveguide 34 that absorbs microwave power to prevent the reflection of power flowing in the opposite direction in the rectangular waveguide 34. A load 50 having an impedance is located. In the square waveguide 32, the electromagnetic power output by the polariser 36 flows through the square waveguide 32 towards the polariser 38. With respect to the A channel signal, the circular polarization introduced by the polarizer 36 is canceled by the circular polarization introduced in the opposite direction by the polarizer 38, so that the A channel signal has a linear polarization state of the transmission line 16. Is played. The transmission line 16 is configured as a part of the square waveguide 32 which is the input section 52 of the feed horn 18. With respect to the B channel signal, the various signals are respectively coupled by the coupler 40 from the rectangular waveguide 34 to the square waveguide 32.
Be combined with. Each coupler 40 transmits a B channel signal to the square waveguide 32 in the same direction as the A channel signal propagates.
It operates directionally so as to be incident on. Arrow 54 of combiner 40
Indicates the propagation direction of the B channel signal through the combiner 40.

2 and 3 show the structure of the coupler 40 according to the first embodiment of the present invention. In addition to the section of each waveguide 32,34, each coupler 40 further comprises two cylindrical cavity filters 56,58 connecting the two waveguides 32,34.
Each filter 56, 58 comprises a side wall 60, a top end wall 62, and a bottom end wall 64. In the case of the first filter 56, the side wall 60 extends through the side wall 42 of the square waveguide 32 to couple electromagnetic power between the filter 56 and the square waveguide 32. Is provided. The holes 66 take the form of elongated slots and are shown in broken lines in FIG. 2 and in cross section in FIG. Second hole
68 is formed in the bottom end wall 64 of the first filter 56 and maintains power coupling between the filter 56 and the rectangular waveguide 34 through the top wall 44 of the rectangular waveguide 34. The second hole 68 has the form of an elongated slot. A third hole 70 in the form of an elongated slot is formed in the side wall 60 of the second filter 58 and has a rectangular waveguide 34 for coupling the power between the second filter 58 and the rectangular waveguide 34. Extending through the narrow wall 48 of. A fourth hole 72 in the form of an elongated slot is formed in the upper end wall 62 of the second filter 58 and is a square waveguide for coupling the power between the second filter 58 and the square waveguide 32. It extends through 32 sidewalls 42.

The orientation of each hole 66, 68, 70, 72 is determined by the waveguide 3
2,34 and the respective filters 56,58 provide magnetic coupling by the H component of the various electromagnetic fields. Typically each filter 56,68
Comprises two cavities 74,76 separated by a transverse plate 78 having a coupling iris 80 such as a circular iris. The design of filters with two cavities is well known. Further, the number of cavities is determined based on the desired characteristics for the passband of each coupler 40. For example, well-defined passbands are needed for closely spaced frequencies of various B-channel signals, while non-well-defined passbands are spaced further apart along the spectrum. Used by signal frequency.

In each coupler 40, two waveguides 32, 34
Are parallel to each other in this embodiment of the invention. A total of four slots 66,68,70,72 are arranged in a common plane transverse to the long axes of the two waveguides 32,34. A second hole located in the bottom end wall 64 of the first filter 56 and a fourth hole 72 located in the top end wall 62 of the filter 58 are transverse to the long axes of the waveguides 32,34. Are arranged vertically. First placed on the side wall 60 of the first filter 56
The holes 66 and the third holes 70 arranged in the side wall 60 of the second filter 58 are arranged in the longitudinal direction parallel to the long axes of the waveguides 32 and 34.

Referring to FIG. 4, the combiner 40 of FIGS.
Another embodiment of combiner 40A is shown. In FIG. 4, the rectangular waveguide 34 is oriented perpendicular to the square waveguide 32. Two filters 56,58 are used for the coupling of electromagnetic power between the two waveguides 32 and 34.
However, the orientation of the two filters 56,58 differs from that shown in FIGS. In FIG. 4, the bottom end wall 64 of each filter 56,58 contacts the sidewall 42 of the square waveguide 32. Each side wall 60 of the filters 56, 58 has a rectangular waveguide 34
Respectively contact the top wall 44 and the narrow sidewall 48 of the.
Four coupling holes for coupling electromagnetic power from rectangular waveguide 34 to square waveguide 32 through two filters 56,58
82,84,86,88 are provided. A first hole 82 having the form of an elongated slot extends through the sidewall 60 of the first filter 56 and the top wall 44 of the rectangular waveguide 34 and is oriented transverse to the longitudinal axis of the rectangular waveguide 34. ing. The second hole 84 extends through the bottom end wall of the first filter 56 and the side wall 42 of the square waveguide 32 and has the form of an elongated slot having a longitudinal direction parallel to the axis of the square waveguide 32. The third hole 86 is located in the bottom end wall 64 of the second filter 58, penetrates the sidewall 42 of the square waveguide 32, and has a longitudinal direction transverse to the long axis of the square waveguide 32. It has the form of an elongated slot. The fourth hole 88 is located in the side wall 60 of the second filter 58, extends through the narrow wall 48 of the rectangular waveguide 34, and has an elongated slot having a longitudinal direction parallel to the long axis of the rectangular waveguide 34. Has the form of.

The transverse dimensions of the waveguides 32,34 are shown in FIG. 4, and the transverse dimension or width of the sidewall 30 of the square waveguide 32 is indicated by the letter a. Furthermore, the top wall 44 and bottom wall 46 of the rectangular waveguide 34 have a width equal to the dimension a. The narrow wall 48 of the rectangular waveguide 34 has a width b equal to half a. The diameter of each filter 56,58 is approximately equal to the dimension a. If desired, the filters 56,58 can be constructed with multiple cavities as shown in FIG.

2 having multiple signals with different frequencies
The configuration of a multiplexing system suitable for combining multiple signal channels has been described above. The configuration of the multiplexing system provides a combination of both signal channels for propagation along a common transmission line suitable for antenna feed. Furthermore, the coupling is done by providing a linear polarization of the signal of one channel and a circular polarization of the signal of the other channel.

It should be understood that the above-described embodiments of the present invention are exemplary only, and modifications can be easily made by those skilled in the art. Therefore, the present invention is not limited to the embodiments disclosed herein, but only by the appended claims.

[Brief description of drawings]

FIG. 1 is a partial view of a communication satellite system showing multiplexing of two sets of signals by a set of microwave combiners constructed in accordance with the present invention.

FIG. 2 is a perspective view of the coupler of FIG. 1 according to the first embodiment of the present invention.

3 is a cross-sectional end view of the coupler of FIG. 2 taken along line 3-3 of FIG.

FIG. 4 is a perspective view of the coupler of FIG. 1 according to a second embodiment of the present invention.

[Explanation of symbols]

10 ... Multiplexing system, 12 ... Communication system, 14 ... Artificial satellite, 16 ... Transmission line, 24, 26 ... Signal source, 32, 34 ... Waveguide, 36,
38… Polarizer, 40… Coupler.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H04J 11/00 B (72) Inventor Los A Stramler Manhattan Beach, USA 90266, California 90266 Ace Street 1461 1/2 (72) Inventor Joe Hall Washington State, USA 98383, Iowa Way NW 10855 (56), Silverdale, United States Reference 51-7796 (JP, Y1)

Claims (1)

[Claims] 1. A plurality of electromagnetic wave signals including a first set of circularly polarized A channel signals and a second set of linearly polarized B channel signals are coupled for propagating along a common transmission line. In the combined system, each signal of the first set of circularly polarized A channels is circular.
The second set of linearly polarized B channels having different wavenumbers
Each signal channel is also different frequencies, a first end and have a second end opposite the first end, our frequency of all those of the A channel signal
And the frequency of all B channel signals is transmitted
It has a transmission line included in the band, an input port and an output port, and all the A-channels.
Channel signal is applied to the input port and the output port
A circular polariser connected to the first end of the transmission line , all A-channel signals passing through the circular polariser and along the transmission line at its second end. propagated in part, further, it is arranged in series along said transmission line
Operating at different frequencies of the respective B-channel signals to couple each of the B-channel signals to the transmission line ,
A system comprising a plurality of couplers for propagating in the direction of the second end of the line .