Microwave integrated apparatus for satellite broadcasting receiver

Abstract: The microwave integrated apparatus comprises a housing (4) having a radiation aperture (5). The housing is electromagnetically shielded except for said radiation aperture (5). An insulated substrate (9) is disposed in the housing (4); and an antenna pattern (1) is formed on the insulated substrate. The antenna pattern is capable of receiving or radiating a microwave signal through the radiation aperture (5) of the housing (4). A signal processing means (2) such as a frequency converting circuit is disposed beside the insulated substrate (9) in the housing (4). The signal processing means (2) is connected to the antenna pattern (1) on the insulated substrate (9).

Description: This invention relates to a microwave circuit arrangement such as an antenna-converter arrangement for a satellite broadcasting receiver and, more particularly, to a microwave integrated apparatus which can be applied to such satellite broadcasting receiver. A conventional microwave circuit arrangement for a satellite broadcasting receiver is disclosed in U. S. Patent No. 4,596,047 issued on June 17, 1986, and assigned to the applicant of the present invention. This arrangement includes a parabolic reflector, a primary radiator (hereinafter referred to as a "horn") located at the focus of the parabolic reflector and a frequency converter connected to the horn. Further, the frequency converter includes a printed circuit board accommodated into a metallic case. Generally, the printed circuit board is a discrete circuit structure which comprises a microstrip line circuit formed on a Teflon (RTM) glass cloth substrate, and a large number of discrete circuit compoments such as transistors, diodes, resistors, capacitors, etc. Furthermore, the horn and the printed circuit board are connected to each other through a waveguide - stripline transducer. Therefore, the above-mentioned conventional circuit arrangement involves drawbacks such as the need for a long assembly time, high production cost, a complicated structure, relatively high signal loss, and insufficient characteristics due to many connecting portions. Further, the use of the horn and the converter leads to an antenna-converter arrangement of large size and high cost. United States Patent US-A-4 319 248 describes an integrated spiral antenna-detector device. Fig. 6 of that patent shows a cavity-backed planar spiral antenna-detector device which has a thin plate positioned across the cavity opening. The plate forms a substrate for a pair of interleaved spiral antenna elements, joined at the centre by a miniature diode, all of which are on the inner surface of the plate, facing the cavity. The outer end of one antenna element is connected to the conductive housing forming the cavity, and the outer end of the other antenna element is connected by a lead which passes down the inside of the cavity to an output termination. This takes the form of the centre contact of a connector to receive a coaxial lead. German Laid-open patent specification DE-A-1 918 084 published in 1970, describes a parabolic antenna system which has a mixer and frequency converter constructed with the horn at the focal point of the antenna. An oscillator is located remotely therefrom at a point on the antenna downlead. German Laid-Open patent specification DE-A-2639795 published in 1977, describes a microwave circuit on an insulated substrate which is hermetically sealed into a microwave transparent container, and includes a rod antenna which may be mounted on the substrate or coupled thereto. The sealed circuit may be mounted on a horn or connected to a waveguide. The present invention is defined in claim 1 below, to which reference should now be made. Advantageous features of the invention are set forth in the appendant claims. The invention will now be described by way of example with reference to the drawings, in which:- Fig. 1 is a sectional view of a microwave integrated apparatus embodying the present invention; Fig. 2 is a perspective view showing the appearance of a microwave integrated apparatus of the embodiment shown in Fig. 1; Fig. 3 is a block diagram showing a signal processing circuit contained in an embodiment of the invention; Fig. 4 is a block diagram showing another signal processing circuit contained in an embodiment of the invention; Figs. 5(a) to 5(e) are plan views showing examples of antenna patterns to be applied to the apparatus; Fig. 6 is a perspective view showing a structural example of a satellite broadcasting receiver using the microwave integrated apparatus embodying the present invention; Fig. 7 is a sectional view of a converter part of the satellite broadcasting receiver shown in Fig. 6; and Fig. 8 is a plan view showing the appearance of the embodiment shown in Fig. 1. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. As shown in Figs. 1, 2 and 8, a microwave integrated apparatus embodying the present invention comprises an antenna pattern 1; a frequency converting circuit 2 comprising a monolithic microwave integrated circuit (hereinafter referred to as a MIC), for example; a plurality of terminals 3; and a sealed housing (hereinafter referred to as a case) 4. A metallic film by metallization or metal 6 is applied to the interior of the case 4 except for a portion near a radiation aperture 5 and the terminals 3, for protection from ultraviolet rays and as an electromagnetic shield. The radiation aperture 5 is made of a material which permits the passage of a microwave signal and keeps airtightness, such as glass, ceramics or plastics. The incident microwave signal through the radiation aperture 5 is picked up by the antenna pattern 1. After this, it is amplified and frequency-converted by the frequency converting circuit 2 through a bonding wire 7. The frequency-converted signal, i.e. intermediate frequency (IF) signal is outputted from the terminals 3 through the bonding wire 8. Such a microwave integrated apparatus can be fabricated by a fabrication and assembly process similar to those of ordinary semiconductor devices such as semiconductor memories and charge coupled (CCD) imaging devices. Accordingly, it can be supplied economically on the mass production basis with high producibility by automatic assembly. In Fig. 3 showing a block diagram of the microwave integrated apparatus of the present invention, the frequency converting circuit or signal processing circuit 2 includes a low noise amplifier 2a, a frequency converter 2b and an intermediate frequency amplifier 2c. The frequency converter 2b frequency-converts the amplified microwave signal by a local oscillation signal LO applied thereto from outside and provides the IF signal having a relatively low frequency. In Fig. 4 showing another block diagram of the microwave integrated apparatus of the present invention, a frequency converting circuit 2′ includes a local oscillator 2d in addition to the circuit arrangement shown in Fig. 3. Figs. 5(a) to 5(e) show some examples of antenna patterns to be applied to the microwave integrated apparatus of the present invention. In the drawing, Fig. 5(a) shows a spiral pattern; Fig. 5(b) shows a cross-dipole pattern; Fig. 5(c) shows a 1/4 wavelength tip-open-line pattern; Fig. 5(d) shows a patch pattern; and Fig. 5(e) shows a combined pattern including a plurality of antenna patterns, particularly a plurality of the cross-dipole patterns. The combined pattern is capable of increasing an antenna gain. An optimum antenna pattern is selected depending on polarization of the microwave applied therewith, such as a circular polarized wave and a linear polarized wave. The antenna pattern is formed on an insulation substrate 9 such as alumina ceramics by a thick or thin film technique and mounted into the case 4 as shown in Fig. 1. Further, the substrate 9 may be a semiconductor substrate such as a Si or GaAs substrate constituting the microwave integrated apparatus, and, in this case, it is possible to form the frequency converting circuit 2 on this semiconductor substrate 9 with the antenna pattern, by a semiconductor integration technique. Thus, in this case, the bonding wire 7 between the antenna pattern 1 and the frequency converting circuit 2 can be omitted since a conductive pattern on the semiconductive substrate 9 is applied instead of the bonding wire 7. Therefore, the assembly work of the microwave integrated apparatus can be more simplified. Further, since any degradation of characteristics due to connecting portions can be eliminated, a microwave integrated apparatus having good characteristics can be accomplished. Fig. 6 shows a structural example of an antenna-converter arrangement using the microwave integrated apparatus according to the present invention. In this Figure, a converter unit 12 is disposed at the focal point of a parabolic reflector 11. Fig. 7 shows a sectional view of the converter unit 12 shown in Fig. 6. In Fig. 7, the microwave integrated apparatus 21 of the present invention is mounted together with other circuit components such as a power source stabilization circuit. Reference numeral 23 represents housing of the converter unit 12 which is made of a material permitting the passage of a microwave, such as plastics and it supports a printed circuit board 22 and a signal connector 24. As shown in Figs. 6 and 7, the antenna-converter arrangement using the microwave integrated apparatus of the present invention does not require the horn including the waveguide and a waveguide-coaxial transducer or a waveguide-stripline transducer that have been necessary conventionally, and is therefore extremely simple in structure. Moreover, since the microwave signal is substantially processed inside the microwave integrated apparatus 21 according to the present invention and the IF signal is outputted to the outside, the circuit configuration of peripheral circuits can be simplified remarkably. Further, an economical material such as a phenol substrate can be used for the printed circuit board 22 in place of the expensive Teflon (RTM) glass cloth substrate. Thus, the present apparatus can provide an antenna-converter arrangement which is simple, compact, economical and easy-to-assemble. In this embodiment, another antenna pattern 10 separate from the antenna pattern 1 is disposed at the radiation aperture 5. Therefore, an incident microwave signal passed through this radiation aperture 5 first excites this antenna pattern 10 and is then received by the antenna pattern 1, which is coupled electromagnetically with the antenna pattern 10. After this, the received microwave signal is amplified and subjected to frequency conversion by the frequency converting circuit 2 comprising the MIC chip through a bonding wire 7 and is outputted from the terminal 3 through the bonding wire 8. Thus, since the microwave signal is received by the combination of the antenna pattern 1 with at least one antenna pattern 10, excellent antenna radiation efficiency can be obtained over a wide frequency range by selecting a resonance frequency of each antenna pattern and a coupling coefficient between them while the antenna pattern 1 and the antenna pattern 10 effect double-resonance. Particularly, when constituting a circular polarization wave generation resonance element such as a circular patch pattern (Fig. 5(d)) as the antenna pattern 10 and an excitation element such as a 1/4 wavelength tip-open-line pattern (Fig. 5(c)) as the antenna pattern 1, a good circular polarization antenna radiation characteristic can be obtained. The antenna pattern 10, as shown in Figs. 1 and 8, is formed inside the case 4 by the thick film technique or the metallization technique. Further, it may be alternatively formed on the outer wall of the case 4 at the radiation aperture 5. In addition, it is possible to dispose third and more antenna patterns outside to couple them with the antenna pattern 10. Furthermore, the microwave integrated apparatus of the present invention can be used as a signal processing means of a phased array antenna by coupling it with the antenna radiation elements of the phased array antenna, for example. Although the description given above deals with the receiver, the present invention can be applied to a transmitter in which an IF signal is reversely frequency-converted and power-supplied to be radiated through the antenna pattern, with the structure shown in Figs. 3 and 4. Obviously, the present invention embraces such case. In accordance with the present invention described above, there can be obtained a compact, economical microwave transmitter or receiver which is easy to assemble while reducing connecting points and has a smaller loss but has excellent characteristics by applying the microwave integrated apparatus of the present invention. Furthermore, according to the present invention, the microwave circuit arrangement having excellent characteristics over a wide frequency range is obtained by disposing the second antenna pattern.

Claims: A microwave integrated apparatus comprising: housing (4) having a radiation aperture (5), the housing being electromagnetically shielded except for the radiation aperture; an insulated substrate (9) disposed in the housing; and a first antenna pattern (1) formed on the insulated substrate, the first antenna pattern being capable of receiving or radiating a microwave signal through the radiation aperture of the housing; characterized by a microwave integrated circuit (2) disposed beside the insulated substrate in the housing, the microwave integrated circuit including an RF amplifier (2a) and a frequency converter (2b); and a second antenna pattern (10) disposed at the radiation aperture, the second antenna pattern being in the proximity of the first antenna pattern. A microwave integrated apparatus as claimed in claim 1, in combination with a parabolic reflector (11), wherein the microwave integrated circuit further includes a local oscillator (2d) and an IF amplifier (2c) and is located at a focus position of the parabolic reflector (11).

Inventors: KOGA HISAYOSHI C O NEC CORPORA, WATANABE HIROSHI C O NEC CORPO, KOGA, HISAYOSHI C/O NEC CORPORATION, WATANABE, HIROSHI C/O NEC CORPORATION
Applicants: NIPPON ELECTRIC CO, NEC CORPORATION
Application year: 1989
Main classification: H01Q1
IPC codes: H01Q21, H01Q1, H01Q19, H01Q23