Adjustable antenna and methods

• US 20080266199A1
• Filed: 04/14/2008
• Published: 10/30/2008
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: Pulse Finland Oy (Yageo Corporation)
• Original Assignee: Pulse Finland Oy (Yageo Corporation)
• Inventors: Mikkola, Jyrki, Milosavljevic, Zlatoljub, Isohatala-Lehmikangas, Anne
• Granted Patent: US 8,473,017 B2
• Time in Patent Office: Days
• US Class Current: 343/850
• CPC Class Codes: H01Q 1/241 used in mobile communications, e.g. GSM H01Q1/247, H01Q1/248 take precedence
• CPC Class Codes: H01Q 9/0442 with particular tuning means
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

An adjustable monopole antenna especially intended for the mobile terminals. The adjusting circuit (930) of the antenna is located between the radiator (920) and the antenna port of a radio device and forms, together with the antenna feed conductor (901), a feed circuit. This circuit comprises an adjustable reactance between the feed conductor and the ground in series with the feed conductor or in both of those places. For example, the feed conductor can be connected by a multi-way switch to one of alternative transmission lines, which are typically short-circuited or open at their tail end and shorter than the quarter wave, each line acting for a certain reactance. The antenna operating band covers at a time only a part of the frequency range used by one or two radio systems, in which case the antenna matching is easier to arrange than of a real broadband antenna. The space required for both the radiator and the adjusting circuit is relatively small. There is no need to arrange a coupling to the radiator for the antenna adjusting, which means a simpler antenna structure and thus savings in production costs.

Claims

1-11. -11. (canceled)

12. An adjustable antenna, comprising:

a radiator electrically coupled to an adjusting circuit, said adjusting circuit comprising a plurality of reactive circuits disposed between a feed conductor and a signal ground;

wherein each of said plurality of reactive circuits generates a unique resonance frequency for said antenna.

13. The adjustable antenna of claim 12, further comprising an antenna switch, said antenna switch implementing time divisional sharing between a plurality of transmit/receive components.

14. The adjustable antenna of claim 13, wherein said plurality of transmit/receive components comprise a first transmitter and receiver for a first system, and a second transmitter and receiver for a second, different system.

15. The adjustable antenna of claim 12, wherein said adjusting circuit further comprises at least one switch coupled to said plurality of reactive circuits, said at least one switch electrically coupled to a control feed;

wherein signals received via said control feed trigger said at least one switch to change states thereby selecting one of said plurality reactive circuits.

16. The adjustable antenna of claim 15, wherein said at least one switch comprises two switches disposed in electrical series with one another, said two switches enabling at least four reactive circuits between said feed conductor and said signal ground.

17. The adjustable antenna of claim 16, wherein said at least four reactive circuits comprise a plurality of inductive and a plurality of capacitive electronic components.

18. The adjustable antenna of claim 15, wherein said at least one switch comprises a first and a second state, said first and second states characterized by a first and a second electronic component, respectively, said first and second electronic components disposed in electrical parallel with one another.

19. The adjustable antenna of claim 12, wherein said adjusting circuit comprises a phase shifter and a capacitance diode, said plurality of reactive circuits generated via adjustments generated by a control signal to said capacitance diode.

20. A method of operating an adjustable antenna, said adjustable antenna comprising an adjusting circuit, a radiator and a feed conductor electrically coupling said adjusting circuit to said radiator, said method comprising:

operating said adjusting circuit in a first mode of operation, said first mode of operation associated with a first resonance frequency;

receiving a control signal at said adjusting circuit to change states; and

operating said adjusting circuit in a second mode of operation, said second mode of operation associated with a second resonance frequency.

21. The method of claim 20, wherein said adjustable antenna further comprises an antenna switch coupled between a plurality of transmit/receive nodes, said method further comprising:

operating said antenna switch such that it time-shares between said plurality of transmit/receive nodes.

22. An adjusting circuit useful in an antenna system, said adjusting circuit comprising a plurality of reactive circuits disposed between a feed conductor and a signal ground;

wherein each of said plurality of reactive circuits generates a unique resonance frequency for said antenna.

23. The adjusting circuit of claim 22, wherein said adjusting circuit further comprises at least one switch coupled to said plurality of reactive circuits, said at least one switch electrically coupled to a control feed;

wherein signals received via said control feed trigger said at least one switch to change states, thereby controllably selecting one of said plurality reactive circuits.

24. The adjusting circuit of claim 23, wherein said at least one switch comprises two switches disposed in electrical series with one another, said two switches enabling at least four distinct reactive circuits between said feed conductor and said signal ground.

25. The adjusting circuit of claim 24, wherein said at least four reactive circuits comprise a plurality of inductive and a plurality of capacitive electronic components.

26. The adjustable antenna of claim 23, wherein said at least one switch comprises a first and a second state, said first and second states characterized by a first and a second electronic component, respectively, said first and second electronic components disposed in electrical parallel with one another.

27. The adjustable antenna of claim 22, wherein said adjusting circuit comprises a phase shifter and a capacitance diode, said plurality of reactive circuits generated via adjustments generated by a control signal to said capacitance diode.

28. An adjustable antenna comprising a signal ground, monopole radiator having a feed conductor and an adjusting circuit to displace an operating band of the antenna, wherein the adjusting circuit and feed conductor together form a feed circuit of the antenna, the feed circuit comprising a reactive circuit between the feed conductor and the signal ground and at least one node pair, the reactance of a circuit between the nodes of which pair can be altered to change a resonance frequency of the antenna.

29. An antenna according to claim 28, where the number of said node pairs is one, one node of said pair being located at the feed conductor, and the other node of said pair being located in the signal ground, the circuit between the nodes of said pair comprises at least two inductive elements and a multiple-way switch to comprise a connection between the feed conductor and signal ground through one inductive element at a time.

30. An antenna according to claim 29, wherein said inductive elements comprise transmission lines.

31. An antenna according to claim 30, wherein the number of said transmission lines is three, and the operating bands corresponding thereto collectively substantially cover a frequency range at least 100 MHz wide.

32. An antenna according to claim 31, wherein the frequency range comprises a range of approximately 470-702 MHz associated with a DVB-H system.

33. An antenna according to claim 29, wherein said inductive elements comprise discrete coils.

34. An antenna according to claim 28, wherein the number of said node pairs is one, each node of said pair being located at the feed conductor, the circuit between the nodes of said pair being disposed in series with the feed conductor and comprising at least two capacitive elements and a multiple-way switch to constitute a connection between the nodes through one capacitive element at a time, said reactive circuit comprising a fixedly connected coil.

35. An antenna according to claim 28, wherein said at least one node pair comprises two node pairs, one node of a first of said node pairs being disposed at the feed conductor and the other node of said first pair being disposed at least partly in the signal ground, a circuit between the nodes of said first pair comprising at least two inductive elements and a multiple-way switch to form a connection between the feed conductor and signal ground through one inductive element at a time, and each node of a second pair of said two node pairs being disposed substantially at the feed conductor, the circuit between said second pair of nodes being disposed in electrical series with the feed conductor and comprising at least two capacitive elements and a multiple-way switch to form a connection between the nodes of said second pair through one of said capacitive elements at a time.

36. An antenna according to claim 28, wherein the number of said node pairs is one, one node of said pair being located substantially at the feed conductor and the other node of said pair being associated with the signal ground, and said circuit between the nodes comprising (i) a capacitance diode to change the reactance of the circuit, and (ii) a phase shifter to shift the adjustment range of the reactance of the circuit.

37. An antenna according to claim 29, wherein the adjusting circuit further comprises an LC circuit disposed electrically between the feed conductor and said switch to at least protect the switch against electrostatic discharge.

38. An antenna according to claim 28, wherein said switch is selected from the group consisting of FET, PHEMT or MEMS devices.

39. An antenna according to claim 28, wherein said antenna comprises an inverted L antenna (ILA).