WO2003075398A1

WO2003075398A1 - Multifrequency antenna

Info

Publication number: WO2003075398A1
Application number: PCT/FI2003/000139
Authority: WO
Inventors: Heikki RYHÄNEN
Original assignee: Ryhaenen Heikki
Priority date: 2002-03-01
Filing date: 2003-02-27
Publication date: 2003-09-12
Also published as: AU2003206989A1; FI20020396A0

Abstract

In this publication is described a multifrequency antenna (200) for personal radio transceiver which comprises a groundplane (201), a dielectric material plate (203) which has a space (202) between groundplane (201) and material plate (203), a conductive layer (204) on the surface of dielectric material plate (203) which acts as a resonator plane, several non-conductive slots (209) on the surface of the resonator plane (204), at least one connecting point (210) which connects galvanically resonator plane (204) to grounplane (201) and matching bridge (212). Apparatus of the invention comprising a resonator plane (204) which comprises two conductive layers, first having a shape like ½-part of elongate shape imparting the candlestick (205) and second having a meander shape (214). Such construction could be tuned for example five separate frequency bands.

Description

Multifrequencyantenna

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.

Known planar multifrequency antenna, for example antenna like US6133879, the most significant factor that restricts the use that antenna is the big size of the said antenna, difficulty of manufacturing and defective bandwidth on operation frequency.

On the other hand, the problem is in the fact that the com- bination of for example two planar Pifa-antennas can be tuned to only two frequency bands. The problem can be restrictedly solved with an antenna for example EP0892459, so that there will be several feeding points and short circuit points which electronically steering the antenna. From the point of view of the manufacturing costs of the telephone it would be advantageous, if the complex structures and electronics could be avoided.

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 previously known antenna on schematic section.

Fig. 3 illustrates one embodiment of the invention on schematic overview, which' is on the personal radio transceiver.

Fig.4 illustrates structure and solution of the embodiment of the invention, which is in the personal radio transceiver.

Fig. 5 illustrates one embodiment of the invention on schematic section view, which is on the personal radio transceiver.

Fig. βa-d illustrates on schematic overview various advantageous embodiments of the multifrequency antenna of the personal^' radio transceiver, which is on accordance with the invention.

Fig. 7 illustrates antenna of the invention on advantageous form on cellular telephone.

Fig. 8 illustrates antenna of the invention on advantageous form on cellular telephone. In figures 1 and 2 is presented schematically well known

PIFA-antenna (US6133879) which could operate on tree separate frequencies. Reference number 101 marks electronically conductive layer, which operate as groundplane. Reference number 103 marks electronically conductive layer, which operate as a resonator plane. Reference number 104 illustrates connection part which connect the antenna 103 to groundplane 101. Reference number 105 illustrates a feed point on the surface of the resonator plane 103. Reference number 102 il- lustrates a thick dielectric material layer which have two surfaces and sides. On the lower surface of layer 102 is groundplane 101, and on the upper surface consist a resonator plane 103, which is an planar position with groundplane 101 on top of another. Resonator plane 103 is constructed with several striplines 100,111,121,110,120 which are formed and dimensioned in such manner that antenna 103 have tree resonant frequencies. It is characteristic to antenna 103 that it have shape of elongate candlestick, in which the striplines are separated by several non-conductive slots 106. It is characteristic to function of the antenna 103 that antenna is tuned to resonant frequency by connection part 104 in such manner that antenna have on every functioning modes a quarter wave functioning and a voltage null on connection part 104. It is possible to reduce or increase the number of resonance of the frequencies of the resonator plane 103 by changing the number of non-conductive slots 106. The dimensioning of the resonator plane 103 depending on dielectric value of the material layer 102 in such manner that if dielectric value increase, the size of the antenna and bandwidth reduce.

A multifrequency antenna according to the invention is shown schematically on figures 3,4 and 5.

On figures 3,4 and 5 is shown schematic over- and sectional view of one embodiment of the invention on the personal radio transceiver. Antenna 200 is shown on drawing 3 from top surface whiteout any supporting frames. Antennas 200 resonator plane 204 is electrically conductive tree dimensional layer 205, 214, which is constructed, to surface of material layer 203. Antenna 200 have over all rectangular surface which has been constructed by using several striplines

213,206, and further antenna 200 consist an meandering trace like ^-wavelength conductor 214 which is described on drawings 4 and 5. Material, layer 203 is described on fig. 5 and it has air space 202 between groundplane 201 and material layer 203. Material layer 203 is a parallel position to groundplane 201. Groundplane 201 is formed on personal radio transceiver typically negatively grounded conductors like printed circuit board, shield housing and battery (not presented) . Resonator plane 204 is located to edge area of groundplane 201 of the apparatus and resonator plane 204 is connected by connector part 207 at least one connection point 210 to groundplane 201. Electric conductive striplines 213 of resonator plane 204, non-conductive slots 209, meandering conductor 214, matching bridge 212, dielectric value of material layer 203 and air space 202 is dimensioned and formed in such manner that antenna of figures 3,4 and 5 could be used for example frequency bands like GSM880-960, DCS1710-1880 and UMTS1900-2200Mhz, which contains together four frequency bands. Also GSMl900Mhz frequency band is included to aforementioned frequencies. It is characteristic to rectangular portion 205 that it has a shape like side projection of ^≤-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 200 formed like figure 3 consist parts 213.1,206 formed like letter I and L, which are jointed from other end galvanically to matching bridge 212. 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.4). As show'n on fig. 3, feeding of the antenna is arranged to surface 205 of the plane to part formed like letter I 213.1. Feed point consists metallised trough hole which functioning like connection part between conductive surface of side projection 205 and trace like conductor 214. It is characterized to trace like conductor 214 that it is jointed to surface of projection 205, to it's feed point 208, from the side of the groundplane 201 via metallised trough hole. Other end of the meandering conductor is then first connected to antenna electrode 221 and secondly connected to surface of the plane 205. This method of connection is essential for functioning of the antenna 200. Meander portion 214 is arranged, as shown on fig.4, to meandering outward from edge of portion 205 to towards other end of the ground- plane 201. Meandering part 214 is located advantageously to surface of material layer 203, on the side of the ground- plane 201. Functioning of the antenna is described more closely by referring backwardly mentioned frequency bands.

UMTS 2110-2200Mhz

The tuning of frequency band of interest is depending from di- mensioning of portion 205, in which two strip 213.1, 213.2 are located side by side, non-conductive slot 209.1 and material plate 203 forming a tuning where can be created electromagnetic field E. Tuning of the antenna 200 is depending on length of slot 209.1 which is approximately one quarter of the wavelength. Dielectric medium of material plate 203 effect to length of the slot 209.1 which is shorter with dielectric medium. Length of the slot 209.1 is adjusted by length of the strips 213.1 and 213.2. At the operation frequency the strip 213.1 is active and strip 213.2 acting as a counterweight for tuning in such manner that voltage null is located to closed end of the I-shaped slot 209.1. Arrow E describes an electromagnetic field which is created between the strips 213.1, 213.2. Feedpoint is located to the conductive surface of the strip 213.1 near closed end of the slot in such manner that antenna 200 could be matched to 50ohm radio transceiver.

UMTS 1900-2025Mhz

The tuning of frequency band of interest is depending from dimensioning of portion 205, in which tree L-shaped strips 213.2, 213.3, 213.4, located side by side, non-conductive slots 209.2, 209.3 and material plate 203 forming a doubleresonance where can be created electromagnetic field E. Tuning of the antenna 200 is depending on both length of slots 209.2, 209.3 which are approximately one quarter of the wavelength and the length of the strips 213.2, 213.3. Dielectric medium of material plate 203 effect to lengths of the slots 209.2, 209.3 which is shorter with dielectric medium. Length of the L-shaped slots 209.2, 209.3 are adjusted by the lengths of the L-shaped strips 213.3 and 213.4. At the operation frequency the strips 213.2 and 213.3 are active and strips 213.3 and 213.4 acting as a counterweight for tuning in such manner that voltage null is located to closed end of the L-shaped slots 209.2, 209.3. Arrow E describes an electromagnetic field, which is created between the strips 213.2, 213.3 and 213.4. Closed ends of the non-conductive slots 209.2, 209.3 on the surface of portion 205 are located on conductive surface near the matching bridge 212 in such manner that antenna 200 could be matched to 50ohm radio transceiver on both resonant frequencies .

DCS 1710-1880Mhz

The tuning of frequency band of interest is depending from di- mensioning of portion 205, in which two L-shaped strips 213.4, 213.5 are located side by side, non-conductive slot 209.4 and material plate 203 forming a tuning where can be created electromagnetic field E. Tuning of the antenna 200 is depending on both length of slot 209.4 which is approximately one quarter of the wavelength. Dielectric medium of material plate 203 effect to length of the slot 209.4 which is shorter with dielectric medium. Length of the slot 209.4 is adjusted by length of the strips 213.4 and 213.5. At the operation frequency the strip

213.4 is active and strip 213.5 acting as a counterweight for tuning in such manner that voltage null is located to closed end of the L-shaped slot 209.4. Arrow E describes an electromagnetic field which is created between the strips 213.4, 213.5. Feed- point is located to the conductive surface of the strip 213.1 near closed end of the slot in such manner that antenna 200 could be matched to 50ohm radio transceiver. When operating frequency is reduced, the L-shaped strip 213.5 acting like the L- shaped resonator with groundplane 201 and is matched to resonant frequency by the length of the matching bridge 212.

GSM 880-960Mhz

The tuning of frequency band of interest is depending from ar- rangement, 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 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 ground- plane 201. When groundplane 201 is longer the distance between feedpoint 208 and groundconnection point 210 is slightly increased. Aforementioned and connected meandering portion 214 op- erates on higher frequencies 1710-2200Mhz as a feedline, which doesn' t affect aforementioned functioning modes . One advantage for aforementioned antenna 214 is, that is possible to match very short groundplanes 201 to work as antenna (80mm long) .

Figures 6a-d illustrating various exemplary embodiments of the invention, which describes location of resonator plane 204 of antenna 200 on relation of different personal radio transceivers groundplane 201.

Figure 6a 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 6b 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 6c 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 6d 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 7 illustrating a groundplane 201 and resonator plane 204. 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 sec- ond 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 8 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. Also there is wide range of other types of isotropic antennas 223 to use. 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 4 shows one structural design of multifrequencyantenna of invention on personal radio transceiver. Reference number 203 illustrating a material plate 203 which is formed from a printed circuit board or laminate or plastic. Dielectric value of material plate 203 is advantageously approximately 2-4. 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. Meandering conductor 214 is connected to 208 antenna electrode 221 from its feed point 208. 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 mate- rial plate 203. Experimental size of the resonator plane 204 is 11-14 x 30-35mm. Distance between the resonator plane 204 and groundplane 201 is 3-6mmm.

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 reso- nance (Bluetooth/WLAN) or resonance frequencies could be vary on which are mentioned before.

Claims

1. Combination of personal radio transceiver and an multi- frequency antenna (200) which comprising - a groundplane (201)

- a dielectric material plate (203) which having an space (202) between groundplane (201) and material plate (203)

- a conductive layer (204) on the surface of dielectric material plate (203) which acting as a resonator plane

- several non-conductive slots (209) on the surface of the resonator plane (204)

- at least one connecting point (210) which connecting galvanically resonator plane (204) to groundplane (201) - matching bridge (212)

c h a r a c t e r i z e d in that said resonator plane (204) comprising rectangular conductive layer which having an elongate shape imparting a side projection of ^-part of a candle- stick (205) , aforementioned projection being formed with strips (213), one like letter I (213.1) and others like elongate letter-L (206), which strips (213) are connected from other end galvanically to other side of the matching bridge (212) , and which strips (213) are separated to each others by using non-conductive slots (209) which are narrow and relatively same width, where non-conductive slots (209) between the striplines (213) are limited from closed end to matching bridge 212 and slots (209) are formed like letter I and elongated letter L and open end of the slots are extended to top point of the side projection of the candlestick (205) .

2. Device as claimed in claim l c h a r a c t e r i z e d in that resonator plane (204) comprising on the surface of the plane at least one connection point (208) at portion of letter I (213.1) which connecting the resonator plane (204) to antenna electrode (221) .

3. Device as claimed in claims 1-2 c h a r a c t e r i z e d in that resonator plane (204) comprising separate trace like resonator (214) which is ^-wavelenght long on it's electronic length, and which conductor is located on the edge area of the side projection (205)

4. Device as claimed in claim 3 c h a r a c t e r i z e d in that trace like resonator (214) is connected from it's other end to surface of the side projection (205), it's feed point (208), from the side of the groundplane (201) via metallised trough hole (208).

5. Device as claimed in claims 3-4 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 material plate (203) is plastic.

7. Device as claimed in claims 1-5 c h a r a c t e r i z e d in that material plate (203) is dielectric laminate.

8. Device as claimed in claims 1-7 c h a r a c t e r i z e d in that the space (202) is air space.

9. Device as claimed in claims 1-8 c h a r a c t e r i z e d in that groundplane (201) comprising a PIFA-resonator (222) which is located to second end of the groundplane (201) wherein the resonator plane (2D4) is located to the first end of said groundplane (201) .

10. Device as claimed in claims 1-8 c h a r a c t e r iz e d in that groundplane (201) comprising a isotropic antenna (223) which is located to second end of the groundplane (201) wherein the resonator plane (204) is located to the first end of said groundplane (201) .