Dielectric waveguide

Abstract: A dielectric waveguide which has the a pair of dielectric substrates (1, 2) affixed mutually and a pair of electrically-conductive plates (3, 4) on the external surface of each dielectric plate (1, 2). Each dielectric substrate (1, 2) has a continuous part (1a, 2a) thicker than an other part. A propagating region is formed when the continuous part on an opposing dielectric plate puts together. Furthermore, a circuit (5a, 5b, 6) is formed on the contact surface of the dielectric plates (1, 2). A part (5a) of circuit (5a, 5b, 6) is arranged in a propagating region so as to cause the electromagnetic-field coupling.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric waveguide, particularly a dielectric waveguide for use in a transmission line or an integrated circuit for the millimeter-wave band. 2. Description of the Related Art Recently, the importance of a millimeter-wave has increased. To achieve improvement in a millimeter-wave technique, the integrated-circuit technique is indispensable. Various kinds of dielectric waveguides have been proposed to reduce the transmission loss of the high frequency signal in an integrated circuit. For example, a normal type dielectric line has a dielectric strip provided between two parallel electrically-conductive plates. Similarly, a grooved type dielectric waveguide has a dielectric strip provided between two electrically-conductive plates. A dielectric strip is inserted in grooves provided on the surface of the electrically-conductive plates. A winged type dielectric waveguide has a pair of opposing dielectric plates, a dielectric line provided between the dielectric plates, and electrode plates deposited on the outer surfaces of the dielectric plates. The inventors of the present invention proposed a further new type of dielectric waveguide. The dielectric waveguide is disclosed in a laid open Japanese Patent Application No. Tokkai-Hei-9-23109. The dielectric waveguide has a dielectric strip and a circuit board both provided between two electrically-conductive plates. The circuit board may be in the vicinity of the dielectric strip to achieve the electromagnetic-field coupling between a circuit element on the circuit board and the dielectric strip. Instead, a part of circuit board may be inserted into the dielectric strip to achieve the electromagnetic-field coupling between a circuit element on the circuit board and the dielectric strip. However, to adjust the electromagnetic-field coupling between the circuit element and the dielectric strip, or the electromagnetic-field coupling between a strip line on the circuit board, it is necessary to locate the circuit board included carefully. There is same difficulty when locating a dielectric resonator to electromagnetically couple with a normal type, grooved type or winged type dielectric waveguides. EP-A1-0 767 507 relates to dielectric waveguides. One embodiment of the dielectric waveguides disclosed in EP-A1-0 767 507 comprises dielectric members which have respective protruding sections to form a dielectric waveguide. Conductive films are arranged on the outer surfaces of the dielectric members. A circuit board provided with strip lines is sandwiched between the dielectric members. It is the object of the present invention to facilitate the alignment of a dielectric strip and a circuit board at a time of the assembly of a dielectric waveguide to thus stabilise the characteristics of manufactured dielectric waveguides. This object is achieved by a dielectric waveguide according to claim 1. According to one aspect of the present invention, a dielectric waveguide comprises, a dielectric having successive portions whose thickness are greater than the another portions of the dielectric, a pair of opposing electrodes disposed on the opposite surfaces of the dielectric, wherein the successive portions forms a propagating region with said pair of opposing electrodes, and a circuitry provided in the dielectric so as to being electromagnetically coupled with the successive portions. Since the circuitry may be arranged to the arbitrary positions inside the dielectric using a printing technique for example, a circuit board is unnecessary to implement a circuitry into the dielectric waveguide. This contributes to a size-reduction of a dielectric waveguide. A part of the circuitry may be a line conductor. By inserting a line conductor into the propagating region of the dielectric waveguide, the line conductor and the pair of opposing electrodes constitute a triplate line. A line conversion is performed between the triplate line and a dielectric waveguide. The circuitry may be an electronic component. For example, a compact millimeter-wave circuit module can be comprised by including an oscillator and a detector circuit in the dielectric waveguide. A chamber may be provided in the inside of a dielectric and the dielectric resonator which projects from a dielectric may be provided in a chamber. The dielectric resonator is preferably provided in the vicinity of the propagating region to cause the electromagnetic-field coupling therebetween. The projection of the dielectric resonator may be formed by mould formation for example. Positioning of the dielectric resonator is not necessary when assembling the dielectric waveguide. A further dielectric resonator may be formed in the chamber to form a dielectric filter with another dielectric resonator. It is also possible to use the dielectric resonator as a primary radiator of an antenna device. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a perspective view of a dielectric waveguide according to a first aspect of the present invention wherein a part of an upper dielectric substrate is fractured for explanation purpose. Fig. 1B is a sectional view of the dielectric waveguide of Fig. 1. Fig. 2 is an exploded perspective view of a dielectric waveguide according to a second aspect of the present invention. Fig. 3 is a perspective view of the dielectric waveguide of Fig. 2. Fig. 4A is a sectional view of the dielectric waveguide of Fig. 3 with respect to A - A line. Fig. 4B is a sectional view of the dielectric waveguide of Fig. 3 with respect to B - B line. Fig. 5 is an exploded perspective view of a dielectric waveguide according to a third aspect of the present invention. Fig. 6 is a sectional view of a dielectric filter fabricated in the dielectric waveguide of Fig. 5. Fig. 7A is a sectional view of the dielectric waveguide of Fig. 5. Fig. 7B is a sectional view of the dielectric waveguide of Fig. 5. Fig. 8 is a perspective view of a dielectric waveguide according to a third aspect of the present invention. Fig. 9A and 9B are sectional views of the dielectric waveguide of Fig. 8. Fig. 10 is a exploded perspective view of a dielectric waveguide according to a fourth aspect of the present invention. Fig. 11 is a perspective view of the dielectric waveguide of Fig. 10. Fig. 12A and 12B are sectional views of the dielectric waveguide of Fig. 10. DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION Fig.1 (A) and (B) show the structure of a dielectric waveguide according to a first aspect of the present invention. Dielectric substrates 1 and 2 are laminated. The dielectric substrates 1 and 2 have projections 1a and 2a respectively. The dielectric substrates are laminated so that the projections 1a and 2a are aligned. Electrodes 3 and 4 are provided in the substantially whole surface of each dielectric plate. The dielectric provided between the projections 1a and 1b, the projection 1a and 2a, and the pair of opposing electrodes 3 and 4 form a propagation region. Dielectric other than the propagating region and the a pair of electrodes 3 and 4 form a cut-off region. Line conductors 5a and 5b may be provided on the dielectric substrate 1. Line conductor 5a may be extended to the propagating region. In the propagating region, the line conductors 5a, the electrodes 3 and 4, and the dielectric between the projections form a triplate line. The electronic components 6, such as a semiconductor device, may be connected to the line conductors 5a and 5b. The dielectric waveguide may be produced by the following process for example: Firstly, the dielectric substrate 2 is formed by means of moulding. Any types of materials such as a ceramic, a resin can be used as the dielectric. Next, a circuit pattern is deposited on the dielectric substrate 2. Then, the upper dielectric substrate 3 is formed by means of moulding. Finally, electrodes 2 and 3 are deposited on the upper and lower surfaces of the dielectric. The structure of the dielectric waveguide according to the second embodiment of the present invention is explained with reference to Figs. 2, 3, 4A and 4B. A pair of dielectric substrates 1 and 2 are laminated as shown in Fig. 3 wherein the dielectric substrates are separately shown for convenience' sake. Fig. 3 shows the dielectric waveguide according to the second embodiment of the present invention. Fig. 4 (A) is A - A line sectional view of Fig. 3. Fig. 4 (B) is B - B line sectional view of Fig. 3. Similar to the dielectric waveguide according to the first embodiment, projections 1a and 2a, the dielectric between the projections, and electrodes 3 and 4 form a propagating region. The electrodes 3, 4 may be electrode layers formed on substantially all exterior surfaces of the dielectric substrates 1 and 2. A slot 11 is provided on the upper surface of a cavity 9. An electrode layer is not formed in the slot 11. The line conductors 5a and 5b may be formed on the dielectric substrate 1. The line conductor 5a crosses the propagating portion. The line conductor 5a, the electrodes 3 and 4, and the dielectric under the projections form a triplate line. The Schottky barrier diode 6 may be connected to the line conductors 5a and 5b. One end of the line conductor 5a is grounded via RF filter pattern. Another RF filter pattern is connected to one end of the line conductor 5b. DC bias circuit is further connected to RF filter pattern. Hollows 21 and 22 are provided near the end of protrusions 1a and 2a. When the dielectric substrates 1 and 2 are laminated, the hollows 21 and 22 are aligned to form a single chamber. A part of the propagating region is exposed within the cavity, and forms an open end. By adjusting the distance between the open end and the line conductor 5a, the electromagnetical coupling between the triplate line and the propagating region is adjusted. The electromagnetic wave propagating the dielectric waveguide is transmitted to the Schottky barrier diode 6 via the open end and the line conductor 5a. The electromagnetic wave is detected by the Schottky barrier diode. Furthermore the extension parts 9 and 10 of the dielectric plates 1 and 2 are provided in another end of the protrusion 1a and 2a. The extension parts 9 and 10 are formed at the time of producing the dielectric substrate 1 and 2 by means of moulding for example. Also, cylinder shaped protrusions 7 and 8 are provided in the extension parts. By aligning the protrusions 7 and 8, a dielectric resonator is formed. Further, a cavity is formed by aligning the extension parts 9 and 10 with each other. The dielectric resonator acts as a primary radiator of an antenna. A dielectric lens may be arranged above the slot 11 to improve the diversity of the antenna. The dielectric resonator is excited by the electromagnetic wave incident to the slot 11 along with the major-axis of the dielectric resonator. The incidence signal is transmitted to the dielectric waveguide and propagates the inside of the propagating region in LSM mode. Next, a dielectric waveguide according to the third embodiment of the present invention is explained, referring Fig.5 - 7. Hollows 18 and 19 are provided in the halfway of a propagating region. An alignment of hollows 18 and 19 forms a cavity in the middle of the propagating region. A dielectric filter 12 is inserted into the cavity. The dielectric filter 12 is comprised by the electrodes 13 and 14 arranged on the upper/lower surfaces of the dielectric substrate 17, and the openings 15a and 15b in the electrodes 13. The openings 16a and 16b of the same shape are also provided in the electrode 14. These openings 15a and 16a, 15b and 16b oppose respectively. The cross section of the above-mentioned dielectric filter is shown in Fig.6. The area between the openings 15a and 16a, and the area between the openings 15b and 16b forms TE010 mode dielectric resonators. As shown in Fig. 7A, the dielectric filter 12 is provided in the cavity. The dielectric substrates 1 and 2 and the dielectric resonators are isolated. A recess are formed in the side wall of the cavity to support the dielectric filter 12. The opposing edges of the dielectric filter 12 are supported by the recess. The cavity functions as a cut-off region. One of the dielectric resonator in the cut-off region electromagnetically couples with the propagating region of the dielectric waveguide. The dielectric resonator further couple with another dielectric resonator which is also couples with the propagating region of the dielectric waveguide. In other words, the propagating regions separated by the cavity can be couple with each other via the intervening dielectric filter 12. Figs. 8 and 9 show the structure of a dielectric waveguide according to the fourth embodiment of the present invention. A hollow is provided in one part of the propagating region. The hollow is surrounded with the dielectric substrates 1a and 2a. As shown in Figs. 9A and 9B, the dielectric substrates 1 and 2 are moulded so that a dielectric rod 1b and 2b together forms a single dielectric rod in the hollow. The opening of the hollow is being covered with the dielectric filter 12 mentioned above. Furthermore, the dielectric filter 12 is covered with the cover 20 made from a metal. The arrow in Fig. 9A shows the distribution of the magnetic-field. The hollow forms a cut-off region. The propagating region and the dielectric filter 12 couple with each other. As a result, the propagating regions separated by the hollow are electromagnetically coupled with each other. Figs. 10 - 12 show the structure of a dielectric waveguide according to the fifth embodiment of the present invention. A hollow is provided in a propagating region like the above-mentioned examples. In the hollow, dielectric protrusions 7a, 7b, 8a, and 8b (Fig.12) are provided. When laminating the dielectric substrates 1 and 2, the protrusions are aligned to form respective dielectric resonators. Fig.11 is an perspective view of the assembled dielectric waveguide. Fig.12A is a sectional view about a surface along the propagating region of Fig.11. Fig.12B is a sectional view with respect to the plane crossing the propagating region. The dielectric resonators operate in TE011 mode. The example shows the dielectric waveguide including a band pass filter which has the two resonators. By the similar technique, it is also possible to produce a dielectric waveguide including an amplifier or an oscillator in the propagating region so as to cause electromagnetic coupling therebetween.

Claims: A dielectric waveguide comprising: two dielectric substrates (1, 2) laminated on to each other; a pair of opposing projections (1a, 2a) protruding from the outer surfaces of said respective laminated dielectric substrates (1, 2); electrodes (3, 4) disposed on the outer surfaces of said laminated respective dielectric substrates (1,2) to form a propagating region with said projections (1a,2a), non-protruding portions forming a cut-off region; a circuit pattern (5a, 5b, 6) disposed on the inner surface of at least said one (2) of said two laminated dielectric substrates (1, 2), wherein said dielectric substrates (1, 2) are directly laminated to each other with said circuit pattern (5a, 5b, 6) located therebetween. A dielectric waveguide according to claim 1, wherein said circuit pattern includes a line conductor (5a, 5b) at least a part (5a) of which is inserted into said propagating region. A dielectric waveguide according to claim 1, wherein said circuit pattern (5a) forms a triplate line with said planar electrodes (3, 4), said triplate line couples with said dielectric waveguide to achieve a line conversion. A dielectric waveguide according to one of claims 1 to 3 further comprising: an electronic component (6) disposed on the inner surface of at least said one (2) of said two laminated dielectric substrates (1, 2). A dielectric waveguide according to claim 1 further comprising: a dielectric resonator (7, 8) protruding from said dielectric (1, 2) to couple with said dielectric waveguide. A dielectric waveguide according to claim 1 further comprising: a chamber provided in said dielectric substrates (1, 2), said chamber being located in the vicinity of said propagating region; a dielectric resonator (7a, 8a) disposed in said chamber, said dielectric resonator (7a, 8a) protrudes from a wall of said chamber. A dielectric waveguide according to claim 6 further comprising another second dielectric resonator (7b, 8b) disposed in said chamber, said second dielectric resonator (7b, 8b) being electromagnetically coupled with said first resonator (7a, 8a) so that said first (7a, 8a) and second (7b, 8b) resonators form a filter.

Inventors: NISHIDA HIROSHI, SAITOH ATSUSHI, TANIZAKI TORU, NISHIDA, HIROSHI, SAITOH, ATSUSHI, TANIZAKI, TORU, Nishida, Hiroshi c/o Murata Manufacturing Co. Ltd., Saitoh, Atsushi c/o Murata Manufacturing Co., Ltd., Tanizaki, Toru c/o Murata Manufacturing Co., Ltd.
Applicants: MURATA MANUFACTURING CO, MURATA MANUFACTURING CO., LTD.
Application year: 1998
Main classification: H01P3
IPC codes: H01Q13, H01P1, H01P5, H01P3