Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P5/00—Coupling devices of the waveguide type
  • H01P5/08—Coupling devices of the waveguide type for linking dissimilar lines or devices
  • H01P5/10—Coupling devices of the waveguide type for linking dissimilar lines or devices for coupling balanced lines or devices with unbalanced lines or devices
  • H01P5/107—Hollow-waveguide/strip-line transitions
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P5/00—Coupling devices of the waveguide type
  • H01P5/08—Coupling devices of the waveguide type for linking dissimilar lines or devices
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49016—Antenna or wave energy "plumbing" making

Definitions

• the invention relates to a transition between a rectangular waveguide and a microstrip line.
• Waveguide structures are often well suited for performing passive functions with low losses and high performance (antenna source such as corrugated horns, polarizers, filters, diplexers) more particularly at very high frequencies (centimeter bands and millimeter).
• Planar structures are very well suited for the low-cost, high-volume production of devices integrating passive and active functions using the methods of manufacturing conventional printed circuits at frequencies up to millimeter bands.
• the antenna source, the filter and the polarizer if necessary are produced in waveguide technology while the rest of the signal processing functions (weak amplification noise, mixing and intermediate filtering) are carried out using conventional printed circuit technology.
• European patent n ° 0350324 describes a transition between a waveguide structure and a microstrip transmission line according to which a conductive line is supported inside the waveguide perpendicular to its axis and the microstrip transmission line extends transversely through the wall of the waveguide in a position producing energy coupling between the microstrip transmission line and the conductive line.
• the substrate is slid under the ribbed part waveguide to ensure good mechanical stability and easy assembly.
• a guided structure is produced on a microwave substrate.
• the rectangular waveguide is produced by a double-sided metallization of the microwave substrate associated with metallized holes to produce the lateral faces of the rectangular waveguide.
• the object of the invention is to provide a transition between a rectangular waveguide and a microstrip line which can be manufactured at low cost without assembling several parts.
• the transition is characterized in that it consists of a rectangular rib waveguide produced in a bar of synthetic material, the metallized base of which under the rib extends in the form of a plate of synthetic material constituting a substrate for the microstrip line, the rib having a bottom extending between the upper plane of the rib waveguide and the upper plane of the substrate and the microstrip line being disposed on the upper plane of the substrate in the extension of the bottom of the rib.
• the bottom of the rib has a linear profile.
• the foam plate constituting the substrate has a thickness which varies in a longitudinal direction to modify the width of the microstrip line while maintaining its almost constant characteristic impedance.
• the synthetic material is a dielectric foam having electrical characteristics close to those of air, and
• the foam is a polymetacrylate imide foam.
• Figure 1 shows a block diagram of a transition according to the invention between a rectangular waveguide and a microstrip line.
• FIG. 1 a transition between a rectangular waveguide and a microstrip line is formed by a rectangular rib waveguide G produced in a foam bar of synthetic material which also serves as a substrate for the microstrip line.
• the bar of foam made of synthetic material for example a polymetacrylate imide foam known for its electrical characteristics close to those of air, for its mechanical characteristics of rigidity and lightness and for its low cost price, extends in a longitudinal direction A between two ends 1, 2 between which is formed a shoulder 3 which extends perpendicular to the longitudinal direction A.
• This shoulder 3 defines an upper plane 4 of the rib waveguide and an upper plane 5 of the substrate.
• the upper plane 5 of the substrate is offset perpendicular to the longitudinal direction of the bar of a height H relative to the upper plane 4 of the rib waveguide, the height H corresponding to the height of the rib of the rib waveguide.
• the bottom of the rib 6 of the waveguide G extends between the upper plane 4 of the waveguide and the upper plane 5 of the substrate through
• the metallized base 8 of the rib waveguide which extends under the rib 6 therefore extends in the form of a foam plate constituting the substrate for the microstrip line.
• This metallized base therefore serves as a ground plane for the microstrip line 7.
• the lateral faces 9 and 10 of the foam bar defining the rectangular rib waveguide are also metallized up to the limit of the shoulder 3 although the metallization of the lateral flanks of the plate constituting the substrate of the microstrip line may not not degrade the electrical behavior of the microstrip line.
• the bottom of the rib 6, at the junction with the microstrip line 7, is at a distance E from the ground plane of the microstrip line, this distance E corresponding to the thickness of the substrate at the junction with the rib waveguide.
• the bottom of the rib 6 has a linear profile which allows it to be produced simply by machining, stamping, hot pressing or by cutting the foam bar.
• the rib 6 is centered in the width of the foam bar and its dimensions can be adjusted according to the desired working frequency range by ensuring an adequate gradual passage from the quasi-TEM propagation mode of the microstrip line to the fundamental mode of the guide. Such a progressive passage takes place according to a given profile, linear, exponential or other.
• the minimum length of the profile obtained to ensure correct adaptation over the entire operating range must be of the order of a fraction of the wavelength (for example a quarter of the wavelength) corresponding to the lowest frequency.
• the microstrip line 7 may have a width identical to that of the rib or greater, but it is well known that the width of a microstrip line depends on the thickness of the substrate on which it is arranged as well as its permittivity. Thus, it is possible to adjust the height of the substrate in the junction plane so as to obtain an identical width, or as close as possible to that of the rib. Then to return to the most suitable substrate thickness, for the microstrip line 7, it suffices to gradually vary the thickness of the foam plate constituting the substrate in the longitudinal direction A.
• This variation in thickness is done at quasi-constant characteristic impedance by simultaneously modifying the width of the microstrip line which avoids passing through quarter-wave impedance transformers with discontinuous variation in line width which are the cause of performance degradations ( losses, reduction in bandwidth).
• the impedance adaptation of the microstrip line is illustrated by a continuous linear decrease (shown in broken lines by 11) in the thickness of the substrate in direction A and by a continuous linear decrease (shown in straight lines). interrupted by 12) of the width of the microstrip line over a certain length L of the microstrip line.
• FIGS. 2 to 4 illustrate a method of manufacturing the transition according to the invention in foam technology.
• a foam bar 20 is previously put in a rectangular shape in cross section with dimensions which correspond to the internal dimensions of a rectangular waveguide for operation a priori mono modal in the desired frequency range.
• the foam bar is worked by machining, thermoforming, stamping or the like to form the rib 6.
• the operation of delimiting the rib 6 in the section of the waveguide G can be extended at the section of the microstrip line 7.
• Complete metallization of the foam block 20 can then be performed, the metallization of the rib and the formation of the microstrip line being carried out simultaneously.
• a non-directive metallization may be used by projection or with a brush.
• the foam block is cut transversely at the end of the rib 6 to form the plate-shaped substrate 5 of the microstrip line.
• the transition according to the invention is therefore carried out in one piece using a material of low permittivity, generating low losses and having good mechanical strength which contributes to obtaining a microstrip line whose dimensions are in accordance with those in the waveguide section. Furthermore, the realization of the transition according to the invention makes it possible to obtain electrical and physical continuity between the waveguide and the microstrip line without recourse to impedance transformers of the discontinuous change in line width type.

Landscapes

• Waveguides (AREA)
• Waveguide Aerials (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=32524679

Family Applications (1)

Country Status (11)

Families Citing this family (13)

Family Cites Families (8)

• 2003
  • 2003-01-03 FR FR0300045A patent/FR2849720B1/fr not_active Expired - Fee Related
  • 2003-12-22 JP JP2004567029A patent/JP4263176B2/ja not_active Expired - Fee Related
  • 2003-12-22 BR BR0317729-7A patent/BR0317729A/pt not_active IP Right Cessation
  • 2003-12-22 CN CNB2003801081523A patent/CN1322628C/zh not_active Expired - Fee Related
  • 2003-12-22 WO PCT/FR2003/050201 patent/WO2004066432A1/fr not_active Ceased
  • 2003-12-22 KR KR1020057012057A patent/KR100998207B1/ko not_active Expired - Fee Related
  • 2003-12-22 DE DE60305349T patent/DE60305349T2/de not_active Expired - Lifetime
  • 2003-12-22 EP EP03810852A patent/EP1579528B1/de not_active Expired - Lifetime
  • 2003-12-22 AU AU2003302294A patent/AU2003302294A1/en not_active Abandoned
  • 2003-12-22 MX MXPA05007249A patent/MXPA05007249A/es active IP Right Grant
  • 2003-12-22 US US10/540,642 patent/US7382212B2/en not_active Expired - Lifetime

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events