DE4208058C2 - Waveguide / microstrip transition - Google Patents

Description

The invention relates to a waveguide / micro Stripline transition for the microwave and milli meter wave range and also includes an arrangement of several such transitions.

For many applications in the field of micro and Millimeter-wave technology is now used for planar circuits used, be it in hybrid or monolithically integrated ter form. A common form of line used for this is the microstrip line. Despite all the advantages of the plana Ren lines are always transitions on hollow ladder needed; so z. B. many antennas on hollow managerial techniques. A previously frequently used transition between  The microstrip line and waveguide is e.g. B. in the Articles by T. Q. Ho and Yi-Chi Shih: "Spectral Domain Analysis of E-Plane Waveguide to Microstrip Transitions "; in: IEEE Transactions on Microwave Theory and Techniques, Vol. 37, No. 2, February 1989, pages 388-392.

In this known transition, the microstrip line tion through a relatively small channel in the waveguide guided. The connecting waveguide leads to one side path; on the other side there is also an approx quarter wavelength long, short-circuited waveguide piece attached. This arrangement requires a complex one Waveguide structure, which is also on both sides the planar structure.

Furthermore, in the article by P.L. Sullivan and D.H. Schaubert: "Analysis of an Aperture Coupled Microstrip An tenna "; in: IEEE Transactions on Antennas and Propagation, Vol. AP-34, No. 8, August 1986, pages 977-984 a cop pel structure for feeding an open, planar antenna described in which on a planar substrate idle microstrip line over a coupling slot is arranged in the ground plane of the substrate and the planar antenna is above the coupling slot located.

In this arrangement, the radio frequency energy over the Microstrip line brought up and over the paddock slotted into the planar antenna and from there emitted.  

Finally, in the article by H.O. Check: "A Novel Method of Cavity Resonator Coupling to Microstrip Lines "; in: Proceeding of the European Microwave Conference (EMC), 09.09. until September 12, 1991 in Stuttgart, pages 807-811 a Coupling structure known with which a cavity resonator a microstrip line is coupled. At this time order is the Mi on a first planar substrate stripline with a matching network over one Coupling slot in the ground plane of the substrate arranges. On a second substrate below the paddock slot is arranged a dipole element, which is in the In is a cavity resonator. The radio frequency With this arrangement, energy is supplied via the matching network and the coupling slot on the dipole element. From there the energy is injected into the cavity pelt and excites it to vibrate at the resonance frequency to.

The object of the invention is a Hohllei ter / microstrip line transition to create that is as simple as possible in the construction.

This object is the subject of claim 1 solved.

The subclaims are on Embodiments of the invention directed.

The claimed waveguide / microstrip line transition is characterized in that on a first planar substrate an empty microstrip line over a coupling slot in the ground plane of the sub strats is arranged and that below the paddock  slot in the opening up to the ground plane introduced waveguide a second planar substrate with a dipole element.

A major advantage of the invention is that the transition has a very simple structure in which

• - The waveguide structures only below the planar circuit are arranged;
• - The waveguide with a simple open end on the underside of the first substrate with the planar circuit (just a small one Piece of additional planar substrate with a Di pole element is at this point under the planar Circuit attached);
• - The planar circuit above the waveguide no longer specially shaped, but any shape can be stretched (e.g. this also allows one simple arrangement of several of these transitions tight side by side);
• - by suitable choice of dimensions and materia lien (e.g. different thicknesses and / or di electricity constants of the two substrate materials rialien) the high-frequency power of the Mi stripline practically exclusively in the Waveguide can be coupled and the Ab radiation can be minimized;  
• - The connection between the waveguide and one planar integrated circuit (e.g. one milli Meter Wave Circuitry (MMIC)) through the reason substrate of a hermetically sealed housing is easily produced by.

In the following the invention with reference to the figure he purifies. There is a particularly advantageous embodiment shape of the waveguide / microstrip line transition shown, namely a transition from a rectangular waveguide on a microstrip line.

During this transition, an idling microstrip line 2 is arranged on a first planar substrate 1 . Un Below this line, about a quarter wavelength (λ / 4) the end 20, is located in the mass of base 7 of the substrate 1, an coupling slot. 3 A rectangular waveguide abuts on the back of the planar substrate 1 conductors 6, in the end of which a second planar sub strate to 5 is, on its underside in the interior of the waveguide 6, a dipole element 4 ( "patch") is arranged.

The contour contours 30 and 40 of the coupling slot 3 and the dipole element 4 are rectangular and run parallel to the contour contour 60 of the cross section of the waveguide 6 ; Coupling slot 3 and dipole element 4 are arranged there with their surface extension transverse and symmetrical to the longitudinal axis of the waveguide 6 . This arrangement has the advantage that it can be calculated in a particularly simple manner.

The high-frequency power is coupled into the waveguide 6 from the microstrip line 2 via the coupling slot 3 and the dipole element 4 . By a suitable choice of the element dimensions and the materials, it can be achieved that the high-frequency power is coupled into the waveguide over a sufficiently large bandwidth with good efficiency. An important role here is that the coupling slot is operated significantly below its resonance frequency; As a result, the high-frequency power is almost completely coupled into the waveguide, and only a negligible part is emitted upwards from the planar circuit.

Embodiments of the invention are addressed below: It is possible to have several of the transitions claimed to be combined in one arrangement with one single common first substrate on which the Leerlau apply microstrip lines of the individual transitions are ordered, or with a single common mass footprint of the common first substrate in which the coupling slots of the individual transitions are and on which leads the waveguide of the individual transitions are.

It is also possible, instead of the rectangular waveguide, a waveguide with another, for. B. circular or el lip-shaped cross section or instead of the rectangular outline contours of the coupling slot or the dipole element in Fig. 1 to choose other outline contours of these circuit elements, for example circular or elliptical contours. It may prove useful to choose the contour of the coupling slot or the dipole element so that it runs parallel or at least approximately parallel to the contour of the cross section of the waveguide.

The layer structure shown in FIG. 1 can also be modified. For example, it is possible to provide the second substrate with further layers in order to increase the bandwidth of the arrangement or to protect the dipole element from mechanical destruction. Furthermore, the second substrate can be arranged at a defined distance from the first substrate in the waveguide. The air gap created between the two substrates also increases the bandwidth of the arrangement. It also offers the possibility of arranging the dipole element in it (ie on the top of the second substrate) in order to protect it from mechanical destruction in the manner. Such an arrangement of two separate substrates is also very easy to manufacture.

Claims (8)

1. waveguide / microstrip line transition for the microwaves and millimeter wave range, characterized marked

• - That an idling microstrip line ( 2 ) is arranged on a first planar substrate ( 1 ) above a coupling slot ( 3 ) in the ground plane ( 7 ) of the substrate ( 1 ); and
• - That underneath the coupling slot ( 3 ) in the opening of a waveguide ( 6 ) brought up to the ground plane ( 7 ), a second plana res substrate ( 5 ) with a dipole element ( 4 ) is found.

2. waveguide / microstrip line transition according to claim 1, characterized in that the coupling slot ( 3 ) at a distance of λ / 4 or approximately λ / 4 from the free end ( 20 ) of the microstrip line ( 2 ) is arranged with λ equal to Signal wavelength at the operating frequency. 3. waveguide / microstrip line transition according to one of the preceding claims, characterized in that the waveguide ( 6 ) is a rectangular waveguide or a hollow conductor with a round or elliptical cross-section. 4. waveguide / microstrip line transition according to one of the preceding claims, characterized in that the thickness and / or the dielectric constant (ε _r1 , ε _r2 ) of the two substrates ( 1 , 5 ) is (are) different. 5. waveguide / microstrip line transition according to one of the preceding claims, characterized in that in particular the second substrate ( 5 ) leads out in layers. 6. waveguide / microstrip line transition according to one of claims 1 to 5, characterized in that the Di polelement ( 4 ) on the inside of the waveguide ( 6 ) be sensitive underside of the second substrate ( 5 ) is arranged. 7. waveguide / microstrip line transition according to one of claims 1 to 5, characterized in that between the first and second substrate's an air gap is provided and that the dipole element ( 4 ) is arranged in the air gap on the top of the second substrate. 8. Arrangement of several waveguides / microstrip lines Transitions according to one of the preceding claims, characterized characterized in that at least part of the first sub strate, but preferably all of the first substrates individual transitions to a common first substrate a common ground plane is summarized (are).