Waveguide input apparatus of two orthogonally polarized waves including two probes attached to a common board

Abstract: A waveguide input apparatus (1) of two orthogonally polarized waves includes a waveguide (1a) having two cavities passing through the outer wall thereof to'the interior, a first probe (5) provided protruding from an inner wall of the waveguide (1a) via a first cavity so that the leading end is parallel to a first plane of polarization (2), a second probe (7) provided protruding from the inner wall of the waveguide (1a) via a second cavity so that the leading end is parallel to a second plane of polarization (3), and a circuit board (4) provided at the outer wall of the waveguide (1a) so as to be parallel to the second plane of polarization (3), and having the first probe (5) and the second probe (7) connected thereto. A converter for satellite broadcasting receiver employing this apparatus is also provided.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a waveguide input apparatus of two orthogonally polarized waves. More particularly, the present invention relates to improvement of a waveguide input apparatus of two orthogonally polarized waves characterized in the structure of the waveguide input unit in a converter for satellite broadcasting and communication receiver to receive two electromagnetic waves, each having a plane of polarization orthogonal to each other, and a converter for satellite broadcasting and communication receiver (termed "for satellite broadcasting receiver" hereinafter) using such a waveguide of two orthogonally polarized waves. Description of the Background Art An example of a conventional waveguide input apparatus of two orthogonally polarized waves will be described hereinafter with reference to Figs. 16A-16C. Fig. 16A is a cross sectional view taken along cross section S-S of Fig. 16C. A waveguide input apparatus 90 for two orthogonally polarized waves includes a waveguide 90a for introducing a polarized wave, a probe 25 for receiving a vertically polarized wave, attached to waveguide 90a in a direction parallel to a plane of polarization 2 of a vertically polarized wave, a probe 26 attached to waveguide 90a in a direction parallel to a plane of polarization 3 of a horizontally polarized wave, a short bar 6, a circuit board 27 connected to probe 25 and arranged at a mount 29a in a manner orthogonal to probe 25, a circuit board 28 connected to probe 26 and arranged at a mount 29b in a manner orthogonal to probe 26, and a connecting portion 31 for connecting circuit board 27 and circuit board 28. Waveguide 90a forms a short wall 8 at the inner wall. Two probes 25 and 26 are attached to waveguide 90a in a direction parallel to the two planes of polarization 2 and 3, respectively. The connection between probes 25 and 26 and circuit boards 27 and 28 is effected arranging respective components in an orthogonal manner (in skew lines). At the outer wall of waveguide 90a, mounts 29a and 29b from which probes 25 and 26 protrude, respectively, are provided. Circuit boards 27 and 28 are attached to mounts 29a and 29b, respectively. Plane of polarization 2 and plane of polarization 3 received by waveguide 90a are orthogonal to each other. The vertically polarized wave corresponds to plane of polarization 2, and the horizontally polarized wave corresponds to plane of polarization 3. Probe 25 and short bar 6 are provided to feed vertically polarized waves and transmit a polarized signal to the circuit board. Probe 26 and short wall 8 are provided to feed horizontally polarized waves and transmit a polarized signal to the circuit board. Probes 25 and 26 receive two orthogonally polarized waves respectively. Probe 25 transmits the received polarized signal of plane of polarization 3 to circuit board 27. Probe 26 transmits the received polarized signal of plane of polarization 2 to circuit board 28. Circuit board 28 provides a polarized signal to circuit board 27 via connection portion 31. Circuit board 27 combines the polarized signal from probe 25 and the polarized signal from circuit board 28. Another example of a waveguide input apparatus of two orthogonally polarized waves will be described with reference to Figs. 17A-17C. Fig. 17A is a sectional view taken along a cross section T-T of Fig. 17C. A waveguide input apparatus 100 of two orthogonally polarized waves includes a waveguide 100a, probes 34 and 35 attached in a direction parallel to the two planes of polarization 2 and 3 orthogonal to each other, respectively, and a circuit board 32 connected to probes 34 and 35, and arranged at a mount 33 at an angle of approximately 45° to probes 34 and 35, respectively. Mount 33 of circuit board 32 formed at the outer wall of waveguide 100a has circuit board 32 attached so as to be 45° with respect to the two planes of polarization 2 and 3. Therefore, the two signals from two probes 34 and 35 are received by one circuit board 32. More specifically, probes 34 and 35 receive two orthogonally polarized waves respectively. Probe 34 transmits the received polarized signal of plane of polarization 2 to circuit board 32. Probe 35 transmits the received polarized signal of plane of polarization 3 to circuit board 32. Circuit board 32 combines these polarized signals. In order to amplify and combine the signals received at probes 25 and 26 for output in the waveguide input apparatus having an input structure described with reference Figs. 16A-16C, a circuit for supplying the signals from probes 25 and 26 to respective one of circuit boards 27 and 28 must be provided. Moreover, a signal combine means at one circuit board 27 is needed and a signal from the other circuit board 28 must be transmitted to circuit board 27 with the combine means via a connection portion 31. The above-described transmission of a signal will increase the complexity of the circuit patterns and structures. Furthermore, there is a possibility of increasing signal loss and inducing interference since a polarized signal has an extremely high frequency. The circuit design may be extremely difficult since critical factors must be taken into account for the arrangement of the circuit pattern. In the assembly of a waveguide, two circuit boards 27 and 28 must be attached, and particular care must be exerted from the standpoint of high frequency for connecting the boards to connection portion 3. The task thereof is difficult, resulting in increase of the cost. The waveguide input apparatus having the input structure described with reference to Figs. 17A-17C is advantageous in that wiring for connecting two boards is not required since there is only one board. However, this apparatus requires the precise provision of (two) holes for insertion of probes 34 and 35 at 45° about the center plane with respect to mount 33 of circuit board 32. The structure design of the mount will become complicated. Also, a working skill of a high level is indispensable. This means that the working task will become difficult with a more complex assembly task. As a result, the fabrication cost will be increased. Also, variation in the quality of the mass production becomes greater, so that the performance requirement cannot be met unless adjustment is carried out for each apparatus. JP 07 263 903 A discloses a waveguide input apparatus according to the preamble of claim 1. A converter for satellite broadcasting receiver is known as an apparatus utilizing such a waveguide apparatus of two orthogonally polarized waves. The converter for satellite broadcasting receiver has the above-described problems of the waveguide apparatus of two orthogonally polarized waves. SUMMARY OF THE INVENTION In view of the foregoing, an object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves that allows the circuit design to be facilitated, and a converter for satellite broadcasting receiver using such a waveguide input apparatus. Another object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves that allows the circuit design and the structure design of a probe attach portion to be facilitated and a converter for satellite broadcasting receiver using such a waveguide input apparatus. A further object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves that allows the circuit design, the structure design of a probe attach portion, and probe process to be facilitated, and a converter for satellite broadcasting receiver using such a waveguide input apparatus. Still another object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves that allows the circuit design, the structure design of a probe attach portion, probe process, and probe attachment to be facilitated and a converter for satellite broadcasting receiver using such a waveguide input apparatus. A still further object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves with low fabrication cost that allows the circuit design, the structure design of a probe attach unit, probe process, and probe attachment to be facilitated, and a converter for satellite broadcasting receiver using such a waveguide input apparatus. Yet a further object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves with low material cost that allows the circuit design, the structure design of the probe attach portion, probe process, and probe attachment to be facilitated, and a converter for satellite broadcasting receiver using such a waveguide input apparatus. Yet another object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves with low material cost and assembly process cost that allows the circuit design, the structure design of a probe attach portion, probe process, and probe attachment to be facilitated, and a converter for satellite broadcasting receiver using such a waveguide input apparatus. Yet a still further object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves with low fabrication cost and superior in mass production that allows the circuit design, the structure design of a probe attach portion, probe process, and probe attachment to be facilitated, and a converter for satellite broadcasting receiver using such a waveguide input apparatus. An additional object of the present invention is to provide a waveguide input apparatus of two orthogonally polarized waves with low fabrication cost and superior in mass production and receiver characteristic that allows the circuit design, the structure design of the probe attach portion, probe process and probe attachment to be facilitated, and a converter for satellite broadcasting receiver using such a waveguide input apparatus. A waveguide input apparatus of two orthogonally polarized waves according to the present invention is defined in claim 1. A converter according to the invention is defined in claim 2. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1A, 1B, an 1C are a front sectional view, a side view, and a plan view, respectively, of a waveguide input apparatus of two orthogonally polarized waves according to a first example useful for understanding the invention. Figs. 2A shows the relationship between the input frequency and the cross polarization characteristic of the waveguide input apparatus of two orthogonally polarized waves of the first example. Fig. 2B shows the relationship between the input frequency and the input return loss of the waveguide input apparatus of two orthogonally polarized waves of the first example. Fig. 3 is an exploded perspective view of the waveguide input apparatus of two orthogonally polarized waves according to the first example. Fig. 4 is a schematic block diagram of a satellite broadcasting converter using the waveguide input apparatus of two orthogonally polarized waves according to the first example. Figs. 5, 6, 7 and 8 are front sectional views of a waveguide input apparatus of two orthogonally polarized waves according to second, third, fourth and fifth, examples, respectively, useful for understanding the invention. Fig. 9A, 9B, and 9C are a front sectional view, a side view, and a plan view, respectively, of,the waveguide input apparatus of two orthogonally polarized waves according to a sixth example useful for understanding the invention. Figs. 10A, 10B and 10C are a front sectional view, a side view, and a plan view, respectively, of a waveguide input apparatus of two orthogonally polarized waves according to a seventh example useful for understanding the invention. Figs. 11A and 11B are a plan view and a front sectional view, respectively, of a waveguide input apparatus of two orthogonally polarized waves according to an embodiment of the present invention. Figs. 12A and 12B are a plan view and a front sectional view, respectively, of a waveguide input apparatus of two orthogonally polarized waves according to an eighth example useful for understanding the invention. Fig. 13 is a front sectional view of a waveguide input apparatus of two orthogonally polarized waves according to a ninth example useful for understanding the invention. Figs. 14A and 14B are a plan view and a front sectional view, respectively, of a waveguide input apparatus of two orthogonally polarized waves according to a tenth example useful for understanding the invention. Figs. 15A and 15B are a plan view and a front sectional view, respectively, of a waveguide input apparatus of two orthogonally polarized waves according to an eleventh example useful for understanding the invention. Figs. 16A, 16B, and 16C are a front sectional view, a side view, and a plan view, respectively, of a conventional waveguide input apparatus of two orthogonally polarized waves. Figs. 17A, 17B and 17C are a front sectional view, a side view, and a plan view, respectively, of another conventional waveguide input apparatus of two orthogonally polarized waves. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A waveguide input apparatus 1 of two orthogonally polarized waves according to a first example will be described hereinafter with reference to Figs. 1A-1C. In Figs. 1A-1C and 16A-16C, like elements are denoted by the same reference characters allotted, and their names and functions are identical. Therefore, detailed description thereof will not be repeated here. One plane of polarization 3 (horizontally polarized wave) and a circuit board 4 are located in parallel. The other plane of polarization 2 (vertically polarized wave) and two probes 5 and 7 are located in parallel. Probes 5 and 7 are both connected to circuit board 4. A leading end 10 of a core conductor 9 in probe 7 is bent substantially at right angles protruding in a direction from the inner wall of a waveguide 1a. Probe 7 is inserted from the above of waveguide 1a into a cavity formed therein. Figs. 1A-1C show the state where probe 7 is already attached. As shown in Figs. 1A-1C, a cavity 1b is formed in the state where probe 7 is attached. A zinc die cast, an aluminum die cast, and the like is used mainly as the material of waveguide 1a. As the material of probes 5 and 7, resin such as polyethylene and Teflon is mainly used. As the material of core conductor 9, metal such as brass, nickel and the like is mainly used. According to the first example, the two probes 5 and 7 for receiving two orthogonally polarized waves are connected to the same circuit board 4. The two probes 5 and 7 are attached parallel to each other in a direction orthogonal to the outer wall of waveguide 1a. In contrast to the case where two probes 5 and 7 are connected to separate circuit boards, the circuit design including the arrangement of the circuit pattern of the combining process of two polarized waves which are high frequency signals is simplified. The material cost can be reduced since only one circuit board is required. A waveguide input apparatus of two orthogonally polarized waves with favorable cross polarization characteristic and input return loss can be provided. In contrast to the case where probes 5 and 7 are attached at an angle of 45° at the outer wall of the waveguide, the object of the structure design of the probe attach portion and process of the probe attachment can be simplified using a hole that can be formed with a mold. Also, the probe attach workability is improved. Thus, a waveguide input apparatus of two orthogonally polarized waves can be provided that allows the assembly process cost to be reduced and superior in mass production. The relationship between the input frequency and the cross polarization characteristic, and between the input frequency and the input return loss of the waveguide input apparatus of two orthogonally polarized waves according to the present example will be described with reference to Figs. 2A and 2B in comparison with a conventional case. In the waveguide input apparatus of two orthogonally polarized waves according to the present example, consideration of a high level for the arrangement of the circuit pattern for preventing increase of signal loss and interference of polarized signals having high frequency is no longer required. Therefore, the circuit pattern designing is simplified. The consideration originated from a board manipulating a high frequency signal is also not required in the assembly process for mounting the circuit board. It is appreciated from Figs. 2A and 2B that the cross polarization characteristic and input return loss are improved than those in the conventional waveguide input apparatus of two orthogonally polarized waves. Fig. 3 is an exploded perspective view showing the assembly structure of a converter 61 for satellite broadcasting receiver using the waveguide input apparatus of two orthogonally polarized waves according to the first example. Referring to Fig. 3, probes 5 and 7 are inserted into predetermined holes 1c and 1b, respectively, of a chassis body 45 including a circular waveguide 1a. Here, circuit board 4 is mounted so that the core conductors of probes 5 and 7 pass through respective holes formed in circuit board 4. The core conductors of probes 5 and 7 are connected by soldering and the like to circuit patterns 48 and 49, respectively, formed on circuit board 4. Circuit board 4 and a shield cover 46 are fixed to chassis body 45 by screwing into holes 53 in chassis body 45 respective screws 47 via fixing holes 51 and 52. Circuitry forming the converter is formed on the plane of circuit board 4 facing chassis body 45. This circuitry will be described briefly afterwards. A cover 55 is attached all over chassis body 45 via a waterproof packing. An output terminal 44 is fixed at the backside of chassis body 45. In inserting chassis body 45 into waterproof cover 41, a fixing nut 43 is fitted to output terminal 44 protruding from the backside via a waterproof packing 42 to secure chassis body 45. The vertically polarized wave and horizontally polarized wave in circular waveguide 1a are reflected at short bar 6 and short wall 8 and received by probes 5 and 7, respectively to be sent to the circuit forming the converter on circuit board 4. The signal amplified on circuit board 4 and converted into a signal of intermediate frequency is sent to output terminal 44 fixed to chassis body 45 to be output. Fig. 4 shows the circuit configuration of a converter for satellite broadcasting receiver formed on circuit board 4. Referring to Fig. 4, this converter 61 includes an LNA (Low Noise Amplifier) 62 for amplifying a signal from probes 5 and 7, a filter 63 receiving the output from LNA 62, a local oscillator 68, a mixer 64 for combining the output signals from filter 63 and local oscillator 68 for conversion into a signal with intermediate frequency, an intermediate frequency amplifier 65 for amplifying an output signal of mixer 64 for output via output terminal 44, and a power supply 67 for supplying power to each circuit. LNA 62 includes an amplifier 71 for amplifying an output signal of probe 5, an amplifier 72 for amplifying an output signal of probe 7, a switch 74 for switching between the outputs of amplifiers 71 and 72 under control of the operating voltage of the converter, and an amplifier 73 for amplifying the output of switch 74 and providing the amplified output to filter 63. The polarized wave introduced into waveguide 1a is provided to LNA 62 via probes 5 and 7. Either one is selected by switch 74 to be provided to filter 63. The output signal from filter 63 is combined with the output signal from local oscillator 68 by mixer 64 to be converted into a signal with intermediate frequency. This intermediate frequency signal is further amplified by intermediate frequency amplifier 65 to be output via output terminal 44. By using the waveguide input apparatus of two orthogonally polarized waves according to the first example as the converter for satellite broadcasting receiver, the component cost of the waveguide input apparatus of two orthogonally polarized waves is suppressed to a low level. Since the assembly thereof is easy, the fabrication cost of the converter itself can be reduced. The usage of the waveguide input apparatus of two orthogonally polarized waves of the first example provides the advantage that it is suitable for mass production. Also, the receiver characteristic is made favorable. The converter shown in Figs. 3 and 4 is applicable, not only to the waveguide input apparatus of two orthogonally polarized wave of the first example, but also to the waveguide input apparatus of two orthogonally polarized waves according to the second to eleventh examples and first embodiment of the present invention. A waveguide input apparatus of two orthogonally polarized waves according to the second to fifth examples of the present invention will be described hereinafter with reference to Figs. 5-8 which are sectional views corresponding to cross section I-I of Fig. 1C. As shown in Fig. 5, a waveguide input apparatus 30 of two orthogonally polarized waves according to the second example differs from the waveguide input apparatus shown in Figs. 1A-1C in that a dielectric 11 around core conductor 9 of probe 7a forms a portion 12 of the inner wall of waveguide 30a that seals the hole, and that partial portions 12 and 13 at the surface of dielectric 11 are covered with thin film metals 12a and 13a, respectively. By adjusting the dielectric constant of dielectric 11 so as to match the impedance within the waveguide, and adjusting the bending angle 17 of core conductor 9 so as to match the impedance in the waveguide, a higher performance can be maintained. A waveguide input apparatus of two orthogonally polarized waves according to a third example will be described with reference to Fig. 6. A waveguide input apparatus 40 of two orthogonally polarized waves of the third embodiment differs from the waveguide input apparatus of two orthogonally polarized waves shown in Figs. 1A-1C in that probe 7b includes a dielectric 14 around core conductor 9 and a conductor portion 15 forming a portion of the inner wall of the waveguide. Similarly to the case of Fig. 5, probe 7b seals the hole in waveguide 40a. Conductor portion 15 and dielectric 14 are formed of separate members. Conductor 15 is introduced after insertion of probe 7b. A shoulder 15a is provided to prevent conductor 15 from falling downwards. A higher performance can be maintained by using dielectric 14 having the dielectric constant and configuration of bending portion 16 adjusted so as to match the impedance in the waveguide, and by using a core conductor having the bent angle adjusted. A waveguide input apparatus of two orthogonally polarized waves according to a fourth example will be described with reference to Fig. 7. A waveguide input apparatus 50 of two orthogonally polarized waves differs from the waveguide input apparatus shown in Figs. 1A-1C in that a portion of core conductor 9a of probe 7c has a configuration of a quadrant 18. In contrast to core conductor 9 having a perpendicularly bent configuration as shown in Figs. 1A-1C, reflectance and interference of a signal within the core conductor are reduced to achieve favorable impedance. This means that a signal of a broader band of frequency can be received in good shape and the return loss can be reduced. Therefore, the receiver characteristic is improved. Furthermore, the present example provides the advantage that the working process is easier than that for a probe with a perpendicular bent portion. It is suitable for mass production. An example of a waveguide input apparatus of two orthogonally polarized waves according to a fifth example will be described with reference to Fig. 8. A waveguide input apparatus 60 of two orthogonally polarized waves differs from the waveguide input apparatus of two orthogonally polarized waves shown in Figs. 1A-1C in that a portion of core conductor 9b of probe 7d has a configuration 19 bent 45°. Similar to the case of Fig. 7, reflectance and interference of a signal within the core conductor, particularly at the bending portion, can be reduced to achieve favorable impedance. Therefore, a signal of a broader band of frequency can be received in good shape. Therefore, the receiver characteristic is improved. The present embodiment provides the advantage that the working process is more easy than that of a probe with a perpendicular bent portion. The waveguide input apparatus of the present example is also superior in mass production. According to the above-described second to fifth examples, a waveguide input apparatus of two orthogonally polarized waves that can achieve a further favorable receiver characteristic can be provided by appropriately selecting the material, structure, configuration of the probes and the configuration of the core conductor. A waveguide input apparatus of two orthogonally polarized waves according to a sixth example will be described with reference to Figs. 9A-9C. Fig. 9A is a sectional view taken along cross section IX-IX of Fig. 9C. Elements corresponding to those of the waveguide input apparatus of two orthogonally polarized waves according to the first example described with reference to Figs. 1A-1C have the same reference character allotted. Detailed description thereof will not be repeated here. A waveguide input apparatus 70 of the present sixth example differs from the waveguide input apparatus of Figs. 1A-1C in that probe 5 is located parallel to plane of polarization 2 (vertically polarized wave) and at an angle of 45° to the other probe 20, and that the configuration of leading end 21 of the core conductor of probe 20 is adjusted so as to match the impedance within waveguide 70a. Probe 20 is inserted into the hole in an oblique direction of 45° in waveguide 70a. The length of leading end 21 is selected to be insertable into the hole. According to the sixth example, the two probes 5 and 20 for receiving two orthogonally polarized waves are connected to the same circuit board 4a. Probe 5 is attached in a direction orthogonal to the outer wall of waveguide 70a. In contrast to the case where two probes are connected to separate circuit boards, the circuit design including the arrangement of the circuit pattern for the combine process of two polarized waves which are high frequency signals can be simplified. The material cost can be reduced since only one circuit board is required. A waveguide input apparatus of two orthogonally polarized waves superior in cross polarization characteristic and input return loss can be provided. In contrast to the case where two probes are attached at an angle of 45° with respect to each other at the outer wall of a waveguide, the object of the structure design of the attachment of one probe 5 and the object of the working process of the attachment of probe 5 corresponds to a simple structure using a hole that can be formed with a mold. The attachment workability of probe 5 is improved. Therefore, the assembly working process cost can be reduced. A waveguide input apparatus of two orthogonally polarized waves superior in mass production can be provided. A waveguide input apparatus of two orthogonally polarized waves according to a seventh example will be described hereinafter with reference to Figs. 10A-10C. Fig. 10A is a sectional view taken along the cross section of X-X of Fig. 10C. A waveguide input apparatus 80 of two orthogonally polarized waves differs from the waveguide input apparatus of two orthogonally polarized waves according to the first example described with reference to Figs. 1A-1C in that a probe 23 is provided in a direction parallel to the plane of polarization 3 of a horizontally polarized wave, and that probes 5 and 23 are connected to a circuit board 22 having a circuit board portion 22a and a circuit board portion 22b coupled by a flexible board 24. Assembly is implemented by connecting circuit board 22 to probes 5 and 23 after probes 5 and 23 are attached. The present invention is not limited to the illustrated example where circuit board 22 is coupled by flexible board 24. Circuit board 22 may be a circuit board formed integrally in a similar configuration. Preferably, the corner of the waveguide 80a corresponding to the portion 24 has a round shape. According to the seventh example, two probes receiving two orthogonally polarized waves are connected to the same circuit board 22. The two probes 5 and 23 are attached in a direction orthogonal to respective outer walls of the waveguide. Therefore, in contrast to the case where two probes are connected to separate circuit boards, the circuit design including arrangement of the circuit pattern for the combine process of two polarized waves which are high frequency signals can be simplified. The material cost can be reduced since only one circuit board is required. A waveguide input apparatus of two orthogonally polarized waves superior in cross polarization characteristic and input return loss can be provided. In contrast to the case where two probes are attached at an angle of 45° with respect to each other at the outer wall of a waveguide, the object of the structure design of the probe attachment and the object of the working process of the probe attachment has a simple structure using a hole that can be formed with a mold. The probe attachment workability is improved. Therefore, the assembly process cost can be reduced. A waveguide input apparatus of two orthogonally polarized waves can be provided superior in mass production. A waveguide input apparatus of two orthogonally polarized waves according to an embodiment of the present invention will be described with reference to Figs. 11A-11B. Fig. 11B is a sectional view taken along line XI-XI of Fig. 11A. Elements similar to those of the waveguide input apparatus of two orthogonally polarized waves according to the first example shown in Figs. 1A-1C have the same reference characters allotted. Detailed description thereof will not be repeated here. A waveguide input apparatus 110 of two orthogonally polarized waves of the present embodiment differs from waveguide input apparatus 1 of two orthogonally polarized waves according to the first example shown in Figs. 1A-1C in that a leading end 10e of a probe 7e is attached deviated by a predetermined angle α about the core axis of probe 7e in a plane including the center axis of the waveguide and leading end 10e, and parallel to the plane of polarization of a horizontally polarized wave. By deviating leading end 10e by a certain angle, the distance between leading end 10e and each component, particularly the leading end of probe 5, short bar 6, and short wall 8 is altered to improve the characteristic depending upon the angle. The angle of obtaining favorable characteristic differs depending upon the dimension of each component and variation thereof, the wavelength of the polarized wave of interest, and the like. It is appreciated that favorable characteristics cannot be obtained with a relatively great angle. This angle α is preferably within approximately ±20°, further preferably within approximately ±10° with respect to the attached angle in the first example as 0°. By attaching probe 7e at an angle within this range where favorable characteristic is obtained, error due to variation of the components at the time of fabrication can be eliminated. Therefore, a waveguide input apparatus of two orthogonally polarized waves with favorable characteristic can be obtained. A waveguide input apparatus of two orthogonally polarized waves according to an eigth example will be described with reference to Figs. 12A and 12B. Fig. 12B is a sectional view taken along line XII-XII of Fig. 12A. Components similar to those of the waveguide input apparatus of two orthogonally polarized waves according to the first example described with reference to Figs. 1A-1C have the same reference characters allotted. Detailed description thereof will not be repeated here. A waveguide input apparatus 120 of two orthogonally polarized waves according to the eighth example differs from waveguide input apparatus 1 of two orthogonally polarized waves according to the first example shown in Figs. 1A-1C in that cavity 1b shown in Figs. 1A-1C is absent and a deep groove 120b having a size and depth in which the leading edge 10 of probe 7 can be inserted vertically is formed where probe 7 is to be provided. Another difference is that a cut 120c is formed at the leading end (the deepest portion) in deep groove 120b so that leading end 10 of probe 7 protrudes into waveguide 1a. The size of cut 120c is selected so that leading end 10 can pass therethrough. By inserting probe 7 deep into deep groove 120b vertically and then sliding probe 7 towards the interior of waveguide 1a, leading end 10 of probe 7 projects through cut 120c to protrude into waveguide 1a. The portion of cut 120c other than leading end 10 is blocked by the circumference of probe 7. Such a structure provides the advantage that the cavity formed at the inner wall of waveguide 1a is reduced in size, and the major portion of the inner wall can be formed integrally with the metal conductor. In contrast to the apparatus of the first example, further favorable receiver characteristic and cross polarization characteristic can be maintained. A waveguide input apparatus of two orthogonally polarized waves according to a ninth example will be described with reference to Figs. 13. Fig. 13 is a front sectional view corresponding to the cross section taken along line XII-XII of Fig. 12A. Components corresponding to those of the waveguide input apparatus of two orthogonally polarized waves according to the eighth example described with reference to Figs. 12A-12B have the same reference characters allotted. Therefore, detailed description thereof will not be repeated here. A waveguide input apparatus 130 of two orthogonally polarized waves of the ninth example differs from the waveguide input apparatus 120 of two orthogonally polarized waves according to the eighth example shown in Figs. 12A-12C in that a metal conductor 130 is inserted by compression into a cavity formed after probe 7 inserted into deep groove 120b shown in Figs. 12A-12C is slid and fixed. By inserting metal conductor 131 into the cavity by compression, the transmission loss can be reduced since the transmission impedance can be improved. Thus, receiver characteristic and cross polarization characteristic more favorable than those in the apparatus of ninth embodiment can be maintained. A waveguide input apparatus of two orthogonally polarized waves according to a tenth example will be described with reference to Figs. 14A-14B. Fig. 14A is a front sectional view of a cross section taken along line XIV-XIV of Fig. 14A. In the present drawings, components corresponding to those of the input apparatus of two orthogonally polarized waves of the eighth example shown in Figs. 12A and 12B have the same reference characters allotted. Detailed description thereof will not be repeated here. A waveguide input apparatus 140 of two orthogonally polarized waves according to the eleventh embodiment differs from waveguide input apparatus 120 of two orthogonally polarized waves according to the ninth embodiment of the present invention shown in Figs. 12A-12B in that connection hole 141 of probe 7 formed at circuit board 142 has a configuration of an ellipse aligned with the major axis in the sliding direction of probe 7. This ellipse configuration allows the length L of the portion of leading end 10 protruding into the waveguide to be adjusted before probe 7 is fixed to circuit board 142 by soldering and the like. By this configuration, the impedance within the waveguide and between probes can be adjusted. Receiver characteristics and cross polarization characteristics more favorable than those of the waveguide input apparatus of two orthogonally polarized waves of the eighth example can be maintained. The configuration of connection hole 141 being an ellipse allows the position of probe 7 to be adjusted after fabrication of the waveguide input apparatus of the two orthogonally polarized waves. A waveguide input apparatus of two orthogonally polarized waves according to an eleventh example will be described with reference to Figs. 15A and 15B. Fig. 15B is a front sectional view taken along line XV-XV of Fig. 15A. In the drawings, components corresponding to those of the waveguide input apparatus of two orthogonally polarized waves of the eighth example described with reference to Figs. 12A-12B have the same reference characters allotted. Detailed description thereof will not be repeated here. A waveguide input apparatus 150 of two orthogonally polarized waves of the eleventh example differs from waveguide input apparatus 120 of two orthogonally polarized waves according to the eighth example shown in Figs. 12A-12B in that the inner wall of a deep groove similar to deep groove 120b shown in Figs. 12A and 12B is covered with a dielectric 151 to form a thin deep groove 152 having a size and depth in which the bent portion of core axis 9 can be inserted in a vertical direction (in the direction of the depth of the deep groove). Thin deep groove 152 has an opening towards the interior of the waveguide in the proximity of the bottom. According to the above-described structure, leading end 10 can be made to protrude into the waveguide by sliding core axis 9 after it is inserted into thin deep groove 152. The inner wall of the deep groove portion is covered with dielectric 151. The transmission impedance can be improved with the core conductor and dielectric 151. Receiver characteristic and cross polarization characteristic further preferable than those of the waveguide input apparatus of two orthogonally polarized waves of the eighth example can be maintained. In the above second to eleventh examples and the embodiment of the present invention, a converter for satellite broadcasting receiver using a waveguide input apparatus of two orthogonally polarized waves was not described. However, like the converter for satellite broadcasting receiver described in the first example, a similar converter can be realized without any undue modification by using the waveguide input apparatus of two orthogonally polarized waves described in respective embodiments. It is understood that a similar advantage can be provided.

Claims: A waveguide input apparatus (1, 30, 40, 50, 60, 70, 110, 120, 130, 140, 150) of two orthogonally polarized waves comprising: a waveguide (1a, 30a, 40a, 50a, 60a, 70a) into which a first polarized wave and a second polarized wave respectively having a first plane of polarization (2) and a second plane of polarization (3) orthogonal to each other are introduced, and having one end open and another end closed by a short-circuiting wall (8), said waveguide (1a, 30a, 40a, 50a, 60a, 70a) having two cavities passing through an outer wall thereof to its interior, a first probe (5) protruding from an inner wall of said waveguide (1a, 30a, 40a, 50a, 60a, 70a) via a first said cavity so that a leading end is parallel to said first plane of polarization (2), a second probe (7, 7a, 7b, 7c, 7d, 7e, 20) protruding from the inner wall of said waveguide (1a, 30a, 40a, 50a, 60a, 70a) via a second said cavity so that a leading end is parallel to said second plane of polarization (3), and a circuit board (4, 4a, 142) provided at said outer wall to be parallel to said second plane of polarization (3), and connected to said first probe (5) and said second probe (7e), characterized in that said second probe (7e) is attached to said circuit board (4) so that said leading end (10e) of said second probe (7e) is deviated within a predetermined angle range (±α) about a direction orthogonal to a center axis of said waveguide (1a) in a plane parallel to said second plane of polarization (3). A converter (61) for a satellite broadcasting receiver comprising a waveguide input apparatus (1, 30, 40, 50, 60, 70, 110, 120, 130, 140, 150) of two orthogonally polarized waves according to claim 1, and a satellite broadcasting receiver converter circuit receiving an output of said waveguide input apparatus (1, 30, 40, 50, 60, 70, 110, 120,130, 140, 150) of two orthogonally polarized waves.

Inventors: HIROTA MAKOTO, NAGANO ATSUSHI, HIROTA, MAKOTO, NAGANO, ATSUSHI
Applicants: SHARP KK, SHARP KABUSHIKI KAISHA
Application year: 1998
Main classification: H01P1
IPC codes: H01Q1, H01Q13, H01P1