Abstract:
A monolithically integrated microwave guide component for overcoupling high frequencies includes a first micro-waveguide that is structured on a micro-waveguide chip, and comprises a second micro-waveguide that is structured on a carrier substrate. The microwave guides are contacted to one another by a chip through-plating. The microwave guides each include, in the contact region, an integrated compensating structure that serves to compensate for reflections.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a monolithically integrated microwave guide component.  
         [0003]     2. Description of the Related Art  
         [0004]     Microwave guide components of the generic kind are known. These serve for the coupling in or out of electromagnetic waves of a high frequency which are supplied via a microwave guide. Such microwave guide components consist of a chip in which a conductor configured as a strip line or as a micro-strip line is integrated. This conductor is applied as is known, to the upper side of the chip. Further circuit components, for example, amplifiers. oscillators or the like, can be integrated inside the chip. The chip is arranged on or next to a carrier which likewise has a conductor designed as a strip line or a micro-strip line for the electromagnetic waves. To connect the conductor structures of the chip and of the carrier to one another, it is known to contact these to one another via a bond connection or a ribbon connection. In this connection, it is disadvantageous that such a coupling out of high frequency electromagnetic waves leads, in particular with frequencies above 10 GHz, to increased reflections due to the inductance of the coupling out line. To compensate for these reflections, compensation circuits must be provided. As a rule, this requires high space requirements on the chip. It is furthermore disadvantageous that due to the short wavelength associated with the high frequencies in assembly tolerances between the chip and carrier, or between the line structures and the coupling out line, result in the formation of parasitic elements (capacitances, inductances), which make compensation more difficult.  
         [0005]     It is known from “DBIT—DIRECT BACKSIDE INTERCONNECT TECHNOLOGY”; IEEE, 6/97, to connect the line structures of the chip and of the carrier to one another by a via. With such a via, the reflections caused by the usual bon connection or ribbon connection are admittedly avoided, but the problem of the compensation with the coupling out of RF signals remains unsolved.  
       SUMMARY OF THE INVENTION  
       [0006]     In comparison, the monolithically integrated microwave guide component in accordance with the invention provides the advantage that a compensation on coupling out RF signals is achieved in a simple manner. Since the microwave guides—of both the chip and the carrier—each have an integrated compensation structure in the contact region, the production of the RF coupling out can take place in a simple manner and an electrical design of the contact region can take place at the same time in such a way that a compensation of reflections is possible.  
         [0007]     In one embodiment of the invention, provision is made for the compensation structures to be formed by line sections of the microwave guides which have a line width matched to the transition. The compensation structure can be hereby be integrated in a simple manner by specifying the layout of the microwave guides in the contacting region. It is in particular provided that the microwave guide associated with the chip forms a capacitively acting line section in the contact region and that the microwave guide associated with the carrier forms an inductively acting line section in the contact region. A compensation can be achieved by interaction of these line sections in the contact region with the grounding arrangement of the microwave guide component such that the line structure of the coupling out of RF signals corresponds to that of a 50 ohm standard microwave guide with sufficient accuracy.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:  
         [0009]      FIG. 1  is a schematic section through a monolithically integrated microwave guide component; and  
         [0010]      FIG. 2  is a schematic plan view of the monolithically integrated microwave guide component. 
     
    
       [0011]     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0012]     Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a monolithically integrated microwave guide component  10  in a longitudinal section. Contact region  12  is shown of a first microwave guide  14  with a second microwave guide  16 . Microwave guide  14  is arranged on a chip  18 , for example on a GaAs (gallium arsenide) chip. Chip  18  has, for example, a thickness of 100 μm. Second microwave guide  16  is arranged on a carrier  20 , for example an Al 2 O 3  (aluminum oxide) substrate. Carrier  20  has, for example, a thickness of 254 μm. An upper side  22  of carrier  20  carries a metallic coating  24 , whereas a lower side  26  on carrier  20  carries a metallic coating  28 . Metallic coatings  24  and  28  are galvanically connected via through-contacts (or vias)  30  indicated here. Metallic coatings  24  and  28  serve in a known manner to make available a ground potential for circuits integrated into microwave guide component  10  which are not shown individually. These can, for example, be monolithically integrated in chip  18 .  
         [0013]     As the schematic plan view shown in  FIG. 2  illustrates, microwave guide  14  consists of a first line section  32  of a second line section  34 , and microwave guide  16  consists of a first line section  36  and of a second line section  38 . Line sections  34  and  38  lie in contact region  12 . Metallic coating  24  forms a recess  40  in contact region  12  which is visible in  FIG. 2  and which as it were engages around contact region  12 . Through-contacts  30  through carrier  20  are arranged symmetrically around contact region  12 .  
         [0014]     Microwave guide  14  includes in its line section  32  a width a and in its line section  34  a width b, with line section  34  being wider than line section  32 . A taper structure  42  is formed at the junction between thinner line section  32  and thicker line section  34 .  
         [0015]     Microwave guide  16  has a width c in its line section  36  and a width d in its line section  38 . Here, width d is smaller than width c. In the direct contact region  12 , line section  38  forms a contact zone  44 . Microwave guides  14  and  16  are connected to one another via a through-contact  46  through chip  18 . Through-contact  46  connects line sections  34  and  38 .  
         [0016]     Line sections  32  and  34  of microwave guide  14  and line section  36  of microwave guide  16  are strip lines or micro-strip lines, whereas line section  38  is formed as a coplanar waveguide.  
         [0017]     Line sections  34  and  38  form integrated compensation structures for the compensation of reflections in contact region  12 . Section  22  forms a 50 ohm micro-strip line by arrangement over metallic coating  24  (ground). Line section  36  of microwave guide  16  likewise forms a 50 ohm micro-strip line, with here a tuning having been made to metallic coating  28  at the lower side of carrier  20 .  
         [0018]     Electromagnetic waves can be respectively coupled in or coupled out due to the design of contact region  12  in accordance with the invention. In this connection, either microwave guide  14  can be the input and microwave guide  16  the output or, in the reverse case, microwave guide  16  the input and microwave guide  14  the output. For example, a signal with a frequency of up to 40 GHz, reflection values of &lt;27 dB result for the monolithically integrated microwave guide component in accordance with the invention. The transmission damping at the transition amounts to below 0.3 db here. In addition to the integration of the compensation structures into contact region  12 , it results as a further advantage that, on the assembly of microwave guide component  10 , chip  18  can be applied in a self-adjusting manner to carrier  20 . Contacting takes places by soldering, with the adjustment of chip  18  on carrier  20  taking place in a self-adjusting manner by the surface tension of the solder in the area of contact region  12 . Differences in tolerance on assembly can hereby be reduced to a minimum so that the occurrence of parasitic elements in contact region  12 —which could have an effect on the compensation—are negligibly small.  
         [0019]     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.