Planar balun transformer device
An electric transformer device (balun) is formed on a support plate having a first base face and an opposite second base face. The balun includes a first port ( 40 ) connectable to an electrical line for a differential signal and a second port connectable to an electrical line for a single-ended signal. A first printed conductive track is associated to the first base face of the support plate for connecting the first port to the second port. A printed conductive path is associated to the second base face of the support plate for connecting the first port to the second port. The printed conductive path is formed of a symmetric second and third printed conductive tracks.
1. A method for manufacturing an electric transformer device to adapt an electrical line for a differential signal to an electrical line for a single-ended signal, comprising the steps of:
securing a first metal sheet on a first base face of a support plate;
securing an opposite second metal sheet on a second base face of the support plate;
said first metal sheet and second metal sheet being connected to the first base face and second base face;
performing a selective chemical removal of metal from said first metal sheet and second metal sheet, said selective chemical removal:
shaping a first conductive track associated to said first base face of the support plate, and
shaping a conductive path associated to said second base face of the support plate;
wherein shaping the first conductive track and shaping of the conductive path comprises shaping each of the first conductive track and the first conductive path to have a length of about λ/4, where λ represents a wavelength of the signal at a center of a pass-band of the electric transformer device;
providing for a first port and a second port of the electric transformer device that are connectable to the electrical line for the differential signal and to the electrical line for the single-ended signal, respectively; and
connecting said first port to said second port via said first conductive track and said conductive path.
2. The method according to claim 1 , wherein shaping the conductive path comprises forming a second and a third conductive track that are configured to connect said first port to said second port.
3. The method according to claim 2 , wherein said first, second and third conductive tracks are metal tracks made of copper.
4. The method according to claim 3 , wherein said copper has a thickness ranging between 17 μm and 70 μm.
5. The method according to claim 2 , wherein shaping the first conductive track and shaping of the conductive path comprises shaping said first, second and third conductive tracks to each have a serpentine path.
6. The method according to claim 2 , wherein each of said second and third conductive tracks have a length of about λ/4.
7. The method according to claim 2 , wherein forming comprises shaping said second conductive track to be substantially symmetrical relative to the third conductive track.
8. The method according to claim 2 , further comprising: forming a via at said first port to electrically connect an end of the first conductive track to an end of the second conductive track.
9. A method for manufacturing an electric transformer device to adapt an electrical line for a differential signal to an electrical line for a single-ended signal, comprising the steps of:
securing a first metal sheet on a first base face of a support plate;
securing an opposite second metal sheet on a second base face of the support plate;
said first metal sheet and second metal sheet being connected to the first base face and second base face, respectively, along an entire face surface;
providing for a first port and a second port of the electric transformer device that are connectable to the electrical line for the differential signal and to the electrical line for the single-ended signal, respectively;
performing a selective chemical removal of metal from said first metal sheet and second metal sheet, said selective chemical removal:
shaping a first conductive track associated to said first base face of the support plate, and
shaping a conductive path associated to said second base face of the support plate, wherein shaping the conductive path comprises forming a second and a third conductive track that are configured to connect said first port to said second port; and
connecting said first port to said second port via said first conductive track and said conductive path;
wherein shaping comprises shaping each of said first, second and third conductive tracks to have a length of about λ/4, where λ represents a wavelength of the signal at a center of a pass-band of the electric transformer device.
10. The method according to claim 9 , wherein said first, second and third conductive tracks are metal tracks made of copper.
11. The method according to claim 10 , wherein said copper has a thickness ranging between 17 μm and 70 μm.
12. The method according to claim 9 , wherein said first, second and third conductive tracks each have a serpentine path.
13. The method according to claim 9 , wherein said second conductive track is substantially symmetrical relative to the third conductive track.
14. The method according to claim 9 , further comprising: forming a via at said first port to electrically connect an end of the first conductive track to an end of the second conductive track.