TWI382592B - A circularly polarized patch antenna with a capacitively coupled feed - Google Patents

Description

Circularly polarized panel antenna with capacitive feeding

The invention relates to a panel antenna, in particular to a reduced circularly polarized panel antenna.

With the development of wireless communication, the car satellite navigation system has quickly set off a wave. In addition to the car parts, various global satellite positioning system (GPS) products such as mobile phones, notebook computers, personal navigation systems, etc. have been developed, and the like. Both use circularly polarized signals for transmission.

Since designing a circularly polarized antenna is required to excite two mutually perpendicular polarization components at the same frequency, the amplitudes of the two components are equal and the phases are 90 degrees out of phase. The traditional antenna is designed according to this concept. Taking the fiberglass board as an example, the size is roughly 50×50 mm ² , and the size must be reduced for the convenience of application. In order to meet the goal of light and thin products in today's products, the integration of Global Positioning System (GPS) into products will result in the existing antennas not being able to be installed in the limited space of the product, so the antenna must be smaller and smaller. Generally, the design of the circularly polarized antenna is reduced by implanting the slot on the radiating plate to change the current path, and passive components such as chip resistors and chip capacitors can also be used to reduce the size. However, these methods narrow the range. limited.

Therefore, the present invention proposes a circularly polarized panel antenna with capacitive feeding, the antenna can be operated on a global satellite positioning system (GPS) 1575 MHz. It has good circular polarization characteristics and at the same time achieves the purpose of size reduction.

The circularly polarized planar antenna structure with capacitive feeding according to the present invention comprises: a substrate, a radiating portion, a grounding portion, a feeding electrode, and a feeding port, wherein the substrate is a dielectric material having a first surface and a second surface opposite to the first surface and substantially perpendicular to one of the first surface and the second surface, and having a through hole extending through the substrate. The radiating portion includes a body and a plurality of adjustable arms connected to the body, wherein the body is formed on the first surface and has an opening, and the opening surrounds and surrounds the through hole of the substrate. The ground portion is formed on the second surface of the substrate. The feeding electrode and the radiating portion have an annular non-conducting interval of less than 5 mm, and the annular interval is a coupling gap for capacitive feeding. The feed port is disposed substantially in the through hole, has a start end and an end, the start end is connected to a signal source, and the end is electrically connected to the feed electrode, and the feed port is opposite to the ground plane Non-conducting state.

The invention resides primarily in a plurality of adjustable arms that are coupled to the body of the radiating portion. By adjusting the length or area of the adjustable arm, antenna reduction can be achieved and the global satellite positioning system (GPS) center frequency is approximately 1575 MHz and the invention has good circular polarization characteristics.

The technical content and detailed description of the present invention are as follows with reference to the following figures: Please refer to the first figure, which is the appearance of the circularly polarized planar antenna of the present invention. Stereoscopic view. As shown in the figure, a circularly polarized planar antenna with reduced capacitance and capacitive feeding is shown in the figure, comprising: a substrate 13, a radiating portion 14, a grounding portion 15, and a feeding electrode. 16 and one feed 埠17. The substrate 13 is a dielectric material having a first surface 131 and a second surface 132 opposite to the first surface 131 and a side 133 substantially perpendicular to the first surface 131 and the second surface 132. There is a through hole 134 penetrating the base. The radiant portion 14 has a body 141 formed on the first surface 131 and having an opening 142 surrounding and surrounding the through hole 134, and four adjustable arms 143, 144, 145 connected to the body 141. 146. The grounding portion 15 is formed on the second surface 132 of the substrate 13 and has a non-conducting block 151 near the through hole 134. The feeding electrode 16 is located at the through hole 134 of the first surface 131, and the feeding electrode 16 and the body 141 of the radiating portion have an annular non-conducting interval 161 of less than 5 mm. The interval 161 is the coupling gap of the capacitive feed. The feed port 17 is disposed substantially in the through hole 134 and has a start end 171 and an end end 172. The start end 171 is connected to a signal source 173, and the end end 172 is electrically connected to the feed electrode 16 while The feed port 17 and the ground portion 15 are in a non-conducting state.

Please refer to the second and fourth figures, which are schematic views of the circularly polarized panel antenna of the present invention. As shown in the figure, an opening 142 of the body 141 of the radiating portion on the circularly polarized planar antenna substrate 13 is shown in the figure as an annular non-conducting section 161 around the feeding electrode 16, and the body 141 of the radiating portion The edges extend out of four adjustable arms 143, 144, 145, 146. By Adjusting the length of the adjustable arms 143, 144, 145, 146 can effectively increase the resonant path and reduce the distribution of the resonant frequency.

Please refer to the third and fourth figures, which are the Return Loss and the Smith Chart of the circularly polarized panel antenna of the present invention. The above return loss measurement results show that the antenna of the present invention is suitable for a global positioning system (GPS) center frequency of about 1575 MHz and an impedance bandwidth defined by a voltage standing wave ratio of 2:1 is about 1566 MHz to 1581 MHz, and From the measurement of the Smith chart, it can be found that the impedance exhibits a circularly polarized double resonance phenomenon.

Please refer to the fifth, sixth and seventh figures, which are the Axial Ratio of the circularly polarized panel antenna of the present invention and the two-dimensional measurement field diagram of the circularly polarized panel antenna. It is known from the experimental results that the global satellite positioning system (GPS) 1575 MHz mode falls within the 3 dB axial ratio bandwidth, and the antenna of the invention has a good half power beam path width from the measured circular polarization field. Therefore, the circularly polarized panel antenna of the present invention has good circularly polarized radiation characteristics.

Please refer to the eighth and ninth figures, which are schematic diagrams of other embodiments of the circularly polarized panel antenna of the present invention. In Figure 8, the body 141 of the radiating portion is square and has a slit 88 that extends inwardly from the edge of the body 141 of the radiating portion. By adding the slit 88, the resonant frequency of the circularly polarized wave can be adjusted so that the modal impedance matching of the Global Positioning System (GPS) 1575 MHz falls within the equal impedance circle of the 2:1 VSWR of the Smith chart. In FIG. 9, the body 141 of the radiating portion is square and has two truncations 99. By adding the truncated angle 99, the amplitude and phase of the circularly polarized wave can be adjusted to the horizontal and vertical polarization, so that the antenna of the present invention obtains better performance at the Global Positioning System (GPS) 1575 MHz. Axis ratio bandwidth. The preferred embodiment of the above embodiments provides a preferred circularly polarized radiation pattern.

13‧‧‧Base

131‧‧‧ first surface

132‧‧‧ second surface

133‧‧‧ side

134‧‧‧through holes

14‧‧‧ Radiation Department

141‧‧‧ Ontology

142‧‧‧ openings

143, 144, 145, 146‧‧‧ adjustable arms

15‧‧‧ Grounding Department

151‧‧‧ Non-conducting blocks

16‧‧‧Feed the electrode

161‧‧‧Circular non-conducting interval

17‧‧‧Feeding

171‧‧‧starting end

End of 172‧‧‧

173‧‧‧Signal source

88‧‧‧slit

99‧‧‧Tangle

The first figure is a perspective view showing the appearance of the circularly polarized planar antenna of the present invention.

The second A and B diagrams are schematic views of the circular and polarized planar antenna of the present invention.

The third figure is a Return Loss of the circularly polarized panel antenna of the present invention.

The fourth figure is a Smith Chart of the circularly polarized panel antenna of the present invention.

The fifth figure is an Axial Ratio of the circularly polarized panel antenna of the present invention.

The sixth figure is a two-dimensional measurement field diagram of the circularly polarized panel antenna of the present invention in the XZ plane.

The seventh figure is a two-dimensional measurement field diagram of the circularly polarized panel antenna of the present invention in the YZ plane.

Figure 8 is a schematic view showing a first alternative embodiment of the circularly polarized panel antenna of the present invention.

Figure 9 is a schematic view showing a second alternative embodiment of the circularly polarized panel antenna of the present invention.

13‧‧‧Base

131‧‧‧ first surface

132‧‧‧ second surface

133‧‧‧ side

134‧‧‧through holes

14‧‧‧ Radiation Department

141‧‧‧ Ontology

142‧‧‧ openings

143, 144, 145, 146‧‧‧ adjustable arms

15‧‧‧ Grounding Department

151‧‧‧ Non-conducting blocks

16‧‧‧Feed the electrode

161‧‧‧Circular non-conducting interval

17‧‧‧Feeding

171‧‧‧starting end

End of 172‧‧‧

173‧‧‧Signal source

Claims (3)

A circularly polarized planar antenna having a capacitive feed, comprising: a substrate, a dielectric material having a first surface, a second surface opposite to the first surface, and substantially perpendicular to the first surface One side of the second surface has a through hole penetrating through the substrate; a radiating portion includes a body and a plurality of adjustable arms connected to the body, wherein the body is formed on the first surface and has an opening The opening surrounds and surrounds the through hole of the substrate, and the adjustable arms are formed on the first surface of the substrate and the side of the substrate; a ground portion is formed on the second surface of the substrate, and is close to The through hole has a non-conducting block; a feeding electrode is located at the through hole of the first surface, and the feeding electrode and the radiating portion have an annular non-conducting interval of less than 5 mm, and The annular section is a coupling gap for capacitive feeding; and a feeding port is disposed substantially in the through hole, having a starting end and an end, the starting end is connected to a signal source, and the end is electrically connected To the feed electrode, at the same time The feed port is non-conducting with the ground plane. The circularly polarized panel antenna of claim 1, wherein the body of the radiating portion has more than one slit structure. For example, in the circularly polarized panel antenna of claim 1, the body of the radiating portion has more than one truncated angle at the edge of the diagonal.