WO2005101571A1

WO2005101571A1 - Multifrequency antenna

Info

Publication number: WO2005101571A1
Application number: PCT/FI2005/000163
Authority: WO
Inventors: Heikki RYHÄNEN
Original assignee: Ryhaenen Heikki
Priority date: 2004-04-15
Filing date: 2005-03-22
Publication date: 2005-10-27
Also published as: FI20040540A; FI20040540A0

Abstract

In this publication is described a multifrequency antenna (200) for personal radio transceiver which comprising a groundplane (201), a planar conductive layer (204) which acting as a resonator plane, at least one connecting point (210) which connecting galvanically resonator plane (204) to groundplane (201) and matching bridge (212). Main purpose of invention is add one resonant frequency to EGSM-band. Apparatus of the invention comprising a planar conductive surface (205) and first resonator (214.1) which extending from side area of planar surface (205) and second resonator (214.2) which is above planar surface (205).

Description

Multifrequency antenna

The invention in question is directed to the combination of a personal radio transmitter receiver and antenna, which is in accordance with the introduction of enclosed patent claim 1.

The term 'personal radio transceiver' designates a portable radio transmitter and receiver set for example cellular telephone, a multimedia handset, a portable computer or the different combinations of the aforementioned devices.

Previously known planar multifrequency antennas, like WO/03/075398, most significant factor that restricts the use that antenna is limited bandwidth on EGSM-band.

Because Pifa-antenna is planar, simple structure and easy to manufacture it could be hopeful that aforementioned antenna could be utilized on the personal radio transceiver.

The purpose of the invention is to remove the aforementioned disadvantages and perform simple and inexpensive antenna, which can operate with a sufficient bandwidth and good efficiency in several different frequencies bands.

This has been resolved according to the invention and an apparatus of the invention is characterized by characterizing features set forth in the characterizing clause of claim 1.

Preferred evolutions of the invention are set forth in the non-independent claims . The invention will now be described in more detail with --reference made to the accompanying drawings, in which:

Fig. 1 illustrates previously known antenna on schematic overview.

Fig. 2 illustrates one embodiment of the invention on schematic overview, which is on the personal radio transceiver.

--Tig. 3 illustrates structure and solution of the embodiment of the invention, which is in the personal radio transceiver.

Fig. 4-5 illustrates structural of embodiments of the invention.

Fig. 6 illustrates on schematic section various advantageous embodiments of the multifrequency antenna of the personal radio transceiver, which is on accordance with the invention.

Fig. 7a-c illustrates on schematic over: view various advantageous embodiments of the multifrequency antenna of the personal radio transceiver, which is on accordance with the invention.

Fig. 8-13 illustrates antennas of the invention on advantageous form on cellular: telephones.

Xn figure 1 is illustrated schematically previously known PIFA- antenna (WO/03/075398) which operates on several different bands, and which antenna can create for example four different rresonant frequencies. Antenna 100 is presented in fig. 1 on schematic over view whiteout support frames. The resonator plane 204 of antenna 100 is electric conductive planar surface 205, which is formed to material layer 203. Planar surface 205 is over all rectangular surface, which is constructed with several different striplines 213, 206. Further more resonator plane 204 comprising an meander ^-wave resonator 214, which is connected to planar surface 205, to feed point 208. Resonator 214 existing on edge area of planar surface 205 in such manner, that it limit area which extending from edge of planar surface 205. Material layer 203 is parallel position over groundplane 201 and have air space 202 between groundplane 201 and material layer 202. Groundplane 201 is formed on personal radio transceiver typically negatively grounded conductors like printed circuit board, shield housing and battery (not presented) . Resonator plane 203 is located to edge area of groundplane 201 of device, and resonator plane 204 is connected galvanically with connector part 207 to groundplane 201 at least one point. Electric conductive strips 213 of resonator plane 204, non-conductive slots 209, matching bridge 212 and dielectric constant and air space 202 of material plane 203 is dimensioned and formed in such manner that apparatus of fig.l could operate on EGSM880-960Mhz, DCS1710-188 OMhz, WCDMA1900- 2200Mhz and Bluetooth/WLAN2400-2500Mhz frequencies. Also PCSl900Mhz frequency band is included to aforementioned frequencies. It is characteristic to rectangular portion 205 that it has a shape like side projection of i^-part of elongated candlestick which is constructed by using several parts formed like letter I and L which are separated on each others by using non-conductive slots 209 which are relatively narrow and relative same width. Antenna 100, like presented in fig. 1, comprising main strip 213.1, which have matching bridge 212 on other end of strip 213.1. There is connected galvanically several L-shaped strips 206 to matching bridge 212. which strips 206 are jointed from other end to matching bridge 212. Strips 206 are located inside each other and strips 206 are parallel with main strip 213.1. Non-conductive slots 209 between the striplines 213 are limited from closed end to matching bridge 212, when open end of the slot are extended and formed like letter I and L and extended to top point of the side projection of the candlestick. Resonator plane 204 consists on the surface of plane 205 at least one connecting point 208, where the plane 204 is connected, with connection part 221, galvanically to antenna electrode of the radio transceiver (Fig.3). Feeding of antenna 100 is arranged to main strip 213.1 of side projection 205.

Multifrequency antenna of invention is shown with electric main components in fig. 2, 3 and 6. In fig.2 is described antenna 200, characteristic that antenna 200 comprising spiral trace 214.2 which extending from surface of planar surface 205, and which conductor is located planar position in respect to planar surface 205. Resonator 214.2 is located above planar surface, in such manner that planar surface 205 is between resonator 214.2 and groundplane 201. Other end of resonator 214.2 is connected galvanically to planar surface 205, to connection point 208. Resonator 214.2 is in planar position with planar surface 205, and have space between, planar surface 205 and resonator 214.2. Space is advantageously same as air. Furthermore antenna 200 comprising second trace like resonator 214.1, which extending from side of planar surface 205 and it is planar in respect of planax surface 205. Functioning of antenna 200 is described more closeiy compared to aforementioned frequency bands.

EGSM 880-915

Frequency and tuning of aforementioned band is depending of arrangement, wherein spiral conductor 214.2 and side projection 205 forming a tuning where it could create elec romagnetic field. Resonator 214.2 have electric length approximately ^-part of wave length. It is typical to resonator 2L4.2 that it meander from feedpoint 208 on above edge area- of side projection 205 forming spiral form. Tuning of resonator 214.2 depending over all length, which is manipulated by dielectric constant and thickness of material layer 203. Side projection functioning as counter weight to resonator 214.2, in such manner that voltage null is located to ground connection point 210. Distance between resonator 214.2 and side projection 205 affect to bandwidth. Matching bridge 212 between feedpoint 208 and ground contact 210 forming impedance match to resonator 214.2. which other end is connected galvanically to other end of matching bridge 212, to feed point 208 of portion of side pr-ojection 205 in such manner that is possible to match antenna 200 to 50ohm radio transceiver. Aforementioned and connected meandering portion 214 operates on higher frequencies 1710- 22 OOMhz as a feedline, which doesn't affect much aforementioned fαnctioning modes .

EGSM 925-960Mhz

The tuning of frequency band of interest is depending from arrangement, where the meander conductor 214 and groundplane 201 forming a tuning where can be created electromagnetic field E. Meander conductor is connected from other end to portion 205 by metallised trough hole 208 from the side of the groundplane in such manner that conductor is located to material plate 203 on the side of the groundplane. It is typical for portion 214 that it meandering from connection point 208 towards the edge area of the groundplane 201. It is also possible to carry out the portion 214 in such manner that it is extended outward from area of the groundplane 201. At this point the conductor 214 is not on parallel position to the groundplane 201 and such portion 214 operates like isotropic antenna on respect to groundplane 201. The tuning of the resonator 214 is depending from total length of the trace, which is tuned by dielectric medium of material plate 203, thickness of material plate 203, insulation space 211 and thickness of air space 202. Groundplane 201 acting as counterweight for tuning in such manner that the voltage null is located to ground connection point 210. Feed point 208 of the meander portion 214.1 is located on such distance from ground contact point 210 that antenna 200 is possible to match to 50ohm radio transceiver. Matching bridge 212 between feed point 208 and groundcontact 210 forming an impedance match to meandering conductor 214. Distance between feed point 208 and connection point 210 varying slightly from which is the size of the groundplane 201. When groundplane 201 is longer the distance between feedpoint 208 and groundconnection point 210 is slightly increased. Aforementioned and connected meandering portion 214 operates on higher frequencies 1710-2200Mhz as a feedline, which doesn't affect aforementioned functioning modes.

1710-2500Mhz

Functioning of aforementioned frequencies is described closely on patent application WO/03/075398. Non-conductive slot 209 create resonance frequency. Frequency depending primarily length of slot 209 and secondary width of slot 209. Material layer 203 affect to resonant frequency in such manner that it lower it. That enable smaller size to antenna 200. Like fig. 2 side projection 205 comprising strips like letter L, which are characterized that outermost pair of striplines 206.2 are substantially narrower than innermost L-shaped strips 206.1. Although in fig. 2 and 4 antennas 2,00 counterweight 201 comprising on surface of groundplane integrated independent F- antenna 224, which is on edge area of groundplane 201. Such antenna 224 is useful on Bluetooth/WLAN band.

In fig. 4 and 5 illustrating various form of antenna, wherein antenna is constructed to single material plate 203. Dielectric constant of material plate 203 is about 1, when second resonator 214.2 is located on upper area of side projection 205, in such manner that side projection 205 and first resonator 214.1 are both on side of groundplane 201 of material plate 203. Second ^■ resonator 214.2 is connected advantageously via metallised hole 208.1 to surface of side projection 205. Drawings illustrates that first resonator 214.1 could have spiral shape. Resonator is connected advantageously to surface of side projection near vicinity of connection point 208.

In fig. 6 illustrating antenna of fig. 2 and 3 in schematic section figure. Antenna is formed to two planar material plates 203.1 and 203.2. Dielectric constant of material layer 203.1 is advantageously 2-4. Dielectric constant of second material layer 203.1 is advantageously about 1. Second resonator 214.2 is connected via metallised hole 208.1 or compared device to surface of side projection 205.

Figures 7a-d illustrating various e-xemplary embodiments of the invention, which describes location of resonator plane 204 of antenna 200 on relation of different personal radio transceivers groundplane 201.

Figure 7a illustrating a groundplane 201 of cellular telephone, which have a resonator plane 204 located to other end of the groundplane 201. Groundplane 201 could have a hinge 215 or groundplane 201 could be extensible .

Figure 7b illustrating a groundplane 201 of communicator (combination of cellular telephone and personal computer) , which have a resonator plane 204 located to other end of the groundplane 201. Groundplane 201 could have a hinge 215. Figure 7c illustrating a groundplane 201 of personal computer, which have a resonator plane 204 located to PC-card of the computer. Groundplane 201 could have a hinge 215.

Figure 7d illustrating a groundplane 201 of multimedia terminal telephone, which have a resonator plane 204 located to other side of the groundplane 201. Groundplane 201 could have a hinge 215.

Figure 8 illustrating a groundplane 201 and resonator plane 204. Groundplane could comprising holes 229. Resonating properties of groundplane 201 is improved on EGSM-band by using a resonator 222, which is meandering conductor. Other end of the resonator 222 is connected galvanically to second end of the groundplane 201 and the resonator plane 204 is connected to first end of the groundplane 201. Resonator 222 acting as a passive PIFA- resonator. The basis of using such resonator on especially short groundplanes (under 80mm) is that resonator 222 extending the electronic length of the groundplane 201 and increase bandwidth and gain.

Figure 9 illustrating a groundplane 201 and resonator plane 204. Resonating properties of groundplane 201 is improved on EGSM- band by using an isotropic antenna 223, which is normal mode helix antenna. There is also wide range of other types of isotropic antennas 223, like meander antenna. Other end of the antenna 223 is connected galvanically to second end of the groundplane 201 and the resonator plane 204 is connected to first end of the groundplane 201. Antenna 223 acting as a passive antenna 223. The basis of using such antenna on especially short groundplanes (under 80mm) , is that resonator 222 extending the electronic length of the groundplane 201 and increase bandwidth and gain. Figure 10 illustrating a groundplane 201 and resonator plane 204. Resonating properties of groundplane 201 is improved on EGSM-band by using an linear conductor 225, which is connected galvanically to groundplane 201 and it is located on edge area of groundplane 201 and it runs around edge of groundplane 201. This increase electronic length of groundplane 201.

Figure 11 illustrating a groundplane 201 and resonator plane 204. Resonating properties of groundplane 201 is improved on EGSM-band by using at least one slot 226. This increase electronic length of groundplane 201. Slot 226 is located near resonator plane 204.

Figure 12 illustrating a groundplane 201 and resonator plane 204. Resonating properties of groundplane 201 is improved on EGSM-band by using at least one linear and folded conductor 227. This increase electronic length of groundplane 201.

Figure 13 illustrating a groundplane 201 and resonator plane 204. Resonating properties of groundplane 201 is improved on EGSM-band by using at least one linear conductor 228. Conductor 228 is located on edge area of groundplane 201 and it is connected to other end of groundplane 201 wherein resonator plane 204 is on second end of groundplane 201. This increase electronic length of groundplane 201.

Figure 3 shows one structural design of multifrequencyantenna of invention on personal radio transceiver. Reference number 203 illustrating a material plates 203 which are formed from a printed circuit board or laminate or plastic. Material plate 203 consist metallised surface figures 204 which are manufactured by etching or vacuum metalling. Side project 205 comprising on the side of the groundplane 201, second metal surfaces 220 and 214. Surface 220 and meander conductor 214 are connected to surface of side projection 205 from the side of groundplane 201 by metallised trough holes. Surface 220 acting as a contact surface. The resonator plane 204 and it's connection point 210 is connected to groundplane in such manner that connection devices 207 second end is connected galvanically to groundplane 201 and first end is connected to connection surface 220. Connection device 207 could be for example spring plug or something like that . Material plate 203 of antenna 200 could be fastened to housing of the radio transceiver by means of fastening plug 217. Plastic cover 216 could comprise locking devices 219, which connect the resonator plane 204 to plastic housing. Plugs 217 are part of the plastic cover, which serves as a radome and support frame to antenna 200. Material plate 203 could consist a holes 218 which are matched to plugs 217. Dielectric medium of the radome 216 decrease the resonant frequency of the antenna 200. Antenna 200 could be also integrated to plastic cover 216, which serves as a dielectric material plate 203, for example by vacuum metallisation, or on such manner that the plane 204 in formed to film which have two sides, aforementioned film being attached to plastic cover 216 on injection molding process (not presented) . At this point the plastic cover 216 serves as a dielectric material plate 203. Experimental size of the resonator plane 204 is 10-14 x 32-35mm. Distance between the resonator plane 204 and groundplane 201 is 5-7mmm.

There is presented previously only few antenna arrangements of the invention. There are no limitations according to exemplary embodiments because there is numerous variations according to the invention according to patent clauses. It is obvious to professional that antenna 200 could be use whiteout using it's all frequency bands or there is also possible to create new resonances or resonance frequencies could be vary on which are mentioned before.

Claims

1. Combination of personal radio transceiver and an multifrequency antenna (200) which comprising

- An electric counter weight for antenna, like a groundplane (201)

- a conductive layer (204) which acting as a resonator plane

- at least one connecting point (210) which connecting galvanically resonator plane (204) to groundplane (201)

- matching bridge (212) on surface of resonator plane (204) wherein resonator plane (204) comprising at least two separate portions (205, 214), aforementioned first portion comprising planar conductive surface (205) , and second portion comprising first resonator (214.1) which extending from side of planar conductive surface (205) and having planar trace like shape which limit area which extending outside on edge area of planar conductive surface (205) , is c h a r a c t e r i z e d in that resonator plane comprising second resonator (214.2) which extending from surface of planar conductive surface (205) and which resonator having planar trace like shape which limit planar area above planar surface (205) .

2. Device as claimed in claim I c h a r a c t e r i z e d in that planar conductive surface (205) is between second resonator (214.2) and groundplane (201).

3. Device as claimed in claim 1-2 c h a r a c t e r i z e d in that resonator (214) functioning in resonance like - wave resonator (214).

4. Device as claimed in claim 1-3 c h a r a c t e r i z e d in that other end of resonator (214) is connected to planar surface (205), near vicinity of feed connection point (208).

5. Device as claimed in claims 1-4 c h a r a c t e r i z e d in that trace like resonator (214) is meander.

6. Device as claimed in claims 1-5 c h a r a c t e r i z e d in that trace like resonator (214) is spiral.

7. Device as claimed in claims 1-6 c h a r a c t e r i z e d in that planar surface (205) comprising at least one non- conductive slot (209).

8. Device as claimed in claims 1-7 c h a r a c t e r i z e d in that planar conductive surface (205) is formed like Α.- part of elongated side projection of multi arm candlestick (205), wherein aforementioned side projection (205) comprising main strip (213.1), which have matching bridge (212) on other end of strip (213.1), and wherein matching bridge (212) connecting galvanically to, other side of bridge (212) , plurality of folded strips (206) which are parallel and inside each other and which strips 206 are parallel with main strip 213.1 and which strips (206) are separated from each others by using non-conductive slots (209, where non-conductive slots (209) between the striplines (213) are limited from closed end to near vicinity of matching bridge (212) and slots (209) are formed like folded strips (206) and open end of the slots (209) are extended to top point of the side projection of the candlestick (205) .

9. Device as claimed in claims 1-8 c h a r a c t e r i z e d in that folded strip (206) is formed like letter L.

10. Device as claimed in claims 1-9 c h a r a c t e - r i z e d in that non-conductive slot (209) is formed like letter L.

11. Device as claimed in claims 1-10 c h a r a c t e - r i z e d in that side projection (205) comprising outermost a pair of L-shaped strips 206.2, which strips are substantially narrower than width of innermost strips (206.1).

12. Device as claimed in claims 1-11 c h a r a c t e - r i z e d in that counter weight (201) of antenna (200) comprising F-antenna integrated to conductive surface of counter weight (201) .