CN103490151A - L-waveband broadband circular polarization micro-strip antenna - Google Patents

Abstract

The invention discloses an L-band broadband circularly polarized microstrip antenna, which comprises an upper radiation antenna dielectric substrate and a lower feed network dielectric substrate; a radiation patch is printed on the upper surface of the upper radiation antenna dielectric substrate; the upper layer The lower surface of the radiating antenna dielectric substrate is printed with four coupling patches; the upper surface of the lower feed network dielectric substrate is provided with a ground plate, and the lower surface of the lower feed network dielectric substrate is printed with an input terminal and four The microstrip power division phase-shift feed network at the output end; there is an air gap between the upper radiation antenna dielectric substrate and the lower feed network dielectric substrate; each of the coupling patches is connected to the microstrip power by a metal probe One output end of the phase-shifting feed network is connected; the invention has simple structure, low cost, easy tuning, wide impedance bandwidth and circular polarization bandwidth, and is suitable for applications in maritime satellite communication systems and satellite positioning and navigation system terminals.

Description

A L-Band Broadband Circularly Polarized Microstrip Antenna

technical field

The invention relates to antenna technology in the field of wireless communication, in particular to an L-band broadband circularly polarized microstrip antenna.

Background technique

Broadband Global Area Network (BGAN) is the fourth-generation global mobile satellite communication system provided by the International Maritime Satellite Organization (INMARSAT). Demand, to become a revolutionary communication system that provides safe and reliable audio and video streaming media transmission, email, and network access services to users who move freely around the world. The system works in the L-band, and its receiving and sending frequencies correspond to 1525 ~1550MHz and 1626.5~1660.5MHz. In order to share one antenna for sending and receiving, the working frequency band of the antenna is designed to be 1525-660.5MHz, and the relative bandwidth is 8.5%. The loss is small.

The predecessor of the Global Positioning System (GPS) is a meridian satellite positioning system developed by the US military. After years of development, the system has been integrated into various application fields of national economic construction, national defense construction and social development. Global Positioning System (GPS) can provide functions such as vehicle positioning, anti-theft, driving route monitoring, and call command. And most of the items are connected to the network, so that the items can be easily identified, managed and controlled. The outstanding performance of the Global Positioning System (GPS) over the past years has won the trust of thousands of civilian users all over the world. Its reliability has been proven in the past, and it will also benefit users all over the world for a long time in the future. The L1 frequency range of the global positioning system (GPS) navigation satellite positioning signal is 1575.42MHz±1.02MHz, and the antenna adopts right-handed circular polarization.

Among many types of antennas, microstrip antennas are favored by people and develop rapidly because of their outstanding advantages such as small size, light weight and low cost. Microstrip antennas play an important role in many fields such as wireless communication, radio frequency identification, satellite communication, satellite navigation, command and control systems, and biomedical radiators. However, the inherent impedance bandwidth and circular polarization bandwidth of the microstrip antenna are narrow, and the typical frequency bandwidth is from a few tenths of a percent to a few percent, which greatly limits its performance. Therefore, the development of a broadband circularly polarized microstrip antenna is of great significance.

Contents of the invention

Aiming at the above problems, the present invention develops an L-band broadband circularly polarized microstrip antenna compatible with terminal applications of maritime satellite communication systems and satellite positioning and navigation systems.

Technical means of the present invention is as follows:

A kind of L-band broadband circularly polarized microstrip antenna, comprising an upper radiation antenna dielectric substrate and a lower feed network dielectric substrate; the upper surface of the upper radiation antenna dielectric substrate is printed with a radiation patch; the radiation patch includes a An antenna main radiation patch placed in the center and four parasitic radiation patches symmetrically distributed around the antenna main radiation patch; four coupling patches are printed on the lower surface of the upper radiation antenna dielectric substrate; the lower feeder The upper surface of the network dielectric substrate is provided with a grounding plate, and the lower surface of the lower feed network dielectric substrate is printed with a microstrip power division phase-shift feed network with one input end and four output ends; the upper radiation antenna dielectric substrate and There is an air gap between the dielectric substrates of the lower layer feed network; each of the coupling patches is connected to an output end of the microstrip power division phase-shift feed network through a metal probe; The phase feed network adopts a one-to-four microstrip power split phase-shift feed network composed of T-shaped power dividers;

Further, the metal probe passes through the grounding plate and is insulated from the grounding plate; the grounding plate is provided with a protective hole suitable for the metal probe;

Further, the input end of the microstrip power division phase-shifting feed network is connected to the SMA connector through a 50 ohm impedance line;

Further, the upper radiating antenna dielectric substrate and the lower feeding network dielectric substrate are parallel to each other, and are fixed together by plastic screws to maintain an air gap between the upper radiating antenna dielectric substrate and the lower feeding network dielectric substrate;

Further, the microstrip power division phase shift feed network includes:

a first microstrip line and a second microstrip line with a characteristic impedance of 100 ohms and an electrical length difference of 90 degrees;

Two identical quarter-wavelength microstrip lines I and quarter-wavelength microstrip lines II;

Two identical third microstrip lines and fifth microstrip lines;

Two identical fourth microstrip lines and sixth microstrip lines; the characteristic impedance of the third microstrip line, the fourth microstrip line, the fifth microstrip line and the sixth microstrip line is 100 ohms and the third The electrical length difference between the microstrip line and the fourth microstrip line is 180 degrees, and the electrical length difference between the fifth microstrip line and the sixth microstrip line is 180 degrees;

and two identical short-circuit stubs; one end of the two short-circuit stubs is respectively connected to a quarter-wavelength microstrip line I and a quarter-wavelength microstrip line II, and the other end is connected to a grounding plate through a short-circuit pin;

The microstrip power division phase-shift feeding network divides the signal input through the input terminal A into four output signals with equal power; the input signal passes through the input terminal A, the first microstrip line, and the quarter-wavelength microstrip line I , the third microstrip line and the output terminal B to obtain the first output signal with a phase shift of 0 degrees; the input signal passes through the input terminal A, the first microstrip line, the quarter-wavelength microstrip line I, and the fourth microstrip Line and output terminal C get the second output signal with 180-degree phase shift; the input signal passes through input terminal A, second microstrip line, quarter-wavelength microstrip line II, fifth microstrip line and output terminal D The third output signal with 90-degree phase shift is obtained; the input signal is obtained through the input terminal A, the second microstrip line, the quarter-wavelength microstrip line II, the sixth microstrip line and the output terminal E with a phase shift of 270 degrees. shifted fourth output signal;

Further, the radiation patch and the microstrip power division phase-shifting feed network share a ground plane; the characteristic impedance of the short-circuit stub is 70.7 ohms;

Further, the upper radiation antenna dielectric substrate and the lower feed network dielectric substrate are made of microwave dielectric materials with a thickness of 2 mm and a dielectric constant of 2.65;

Further, distributed capacitance is formed between the antenna main radiation patch and the coupling patch, and both are circular patches; the parasitic radiation patch is an arc-shaped patch; two adjacent parasitic radiation patches A slot is formed between the patch and the main radiation patch of the antenna; the circular polarization characteristics of the L-band broadband circularly polarized microstrip antenna are adjusted by changing the size and position of the parasitic radiation patch and the size and position of the slot;

Further, the size of the coupling patch is adjusted according to the change of the air gap.

Due to the adoption of the above technical scheme, a kind of L-band broadband circularly polarized microstrip antenna provided by the present invention, the radiation patch includes a centered antenna main radiation patch and four symmetrically distributed antenna main radiation patches The surrounding parasitic radiation patch widens the circular polarization bandwidth of the antenna; the metal probe is used to connect the coupling patch and the output end of the microstrip power division phase-shift feeding network, and the coupling patch is adjusted according to the change of the air gap The size of the metal probe realizes the compensation for the inductance introduced by the metal probe and the capacitance introduced by the coupling patch, which broadens the impedance bandwidth of the antenna; The influence of the parasitic radiation of the feed network on the directivity of the antenna is improved, and the performance of the antenna is improved; the microstrip power-splitting phase-shift feed network introduces a short-circuit stub, which ensures the accuracy of the power-splitting phase shift of the feed network, and further broadens the impedance of the antenna Bandwidth and circular polarization bandwidth; the invention has simple structure, low cost, easy tuning, wide impedance bandwidth and circular polarization bandwidth, and is suitable for applications in maritime satellite communication systems and satellite positioning and navigation system terminals.

Description of drawings

Fig. 1 is the structural representation of microstrip antenna described in the present invention;

Fig. 2 is a schematic top view of the microstrip antenna of the present invention;

Fig. 3 is the structural representation of microstrip power division phase-shift feeding network described in the present invention;

Fig. 4 is the schematic diagram of the principle of the microstrip power division phase-shift feeding network of the present invention;

Fig. 5 is the graph that the reflection coefficient of microstrip antenna described in the present invention changes with frequency;

Fig. 6 is a graph showing the variation of vertex-axis ratio with frequency of the microstrip antenna according to the present invention.

In the figure: 1. Upper radiation antenna dielectric substrate, 2. Lower feed network dielectric substrate, 3. Plastic screw, 4. Air gap, 5. Metal probe, 6. SMA connector, 7. 50 ohm impedance line, 11. Antenna main radiation patch, 12. Parasitic radiation patch, 13. Coupling patch, 14. Slot, 21. Ground plate, 22. Microstrip power division phase-shift feeding network, 23. Shorting pin, 211. Protection hole , 221, the first microstrip line, 222, the quarter-wavelength microstrip line I, 223, the second microstrip line, 224, the quarter-wavelength microstrip line II, 225, the third microstrip line, 226 , the fourth microstrip line, 227, the fifth microstrip line, 228, the sixth microstrip line, 229, the output terminal B, 230, the output terminal C, 231, the output terminal D, 232, the output terminal E, 233, short circuit Minor.

Detailed ways

A kind of L-band broadband circularly polarized microstrip antenna shown in Fig. 1, Fig. 2, Fig. 3 and Fig. 4 is characterized in that comprising upper layer radiation antenna dielectric substrate 1 and lower layer feed network dielectric substrate 2; said upper layer Radiating patches are printed on the upper surface of the radiating antenna dielectric substrate 1; the radiating patches include a central antenna main radiating patch 11 and four parasitic radiating patches 12 symmetrically distributed around the antenna main radiating patch 11 The lower surface of the upper radiation antenna dielectric substrate 1 is printed with four coupling patches 13; the upper surface of the lower feed network dielectric substrate 2 is provided with a ground plate 21, and the lower surface of the lower feed network dielectric substrate 2 A microstrip power division phase-shifting feed network 22 with one input port and four output ports is printed; there is an air gap 4 between the upper layer radiation antenna dielectric substrate 1 and the lower layer feed network dielectric substrate 2; each The coupling patch 13 is connected to an output end of the microstrip power division phase-shift feed network 22 through a metal probe 5; the microstrip power division phase-shift feed network 22 adopts a T-shaped power divider One-to-four microstrip power division phase-shifting feed network 22; further, the metal probe 5 passes through the ground plate 21 and is insulated from the ground plate 21; the ground plate 21 is provided with metal probes A protective hole 211 that is compatible with the needle 5; further, the input end of the microstrip power division phase-shifting feed network 22 is connected to the SMA connector 6 through a 50 ohm impedance line 7; further, the upper radiation antenna dielectric substrate 1 and the lower feed network dielectric substrate 2 are parallel to each other, and are fixed together by plastic screws 3 to maintain the air gap 4 between the upper radiation antenna dielectric substrate 1 and the lower feed network dielectric substrate 2; further, the The microstrip power-dividing phase-shifting feed network 22 includes: a first microstrip line 221 and a second microstrip line 223 with a characteristic impedance of 100 ohms and an electrical length difference of 90 degrees; two identical quarter-wavelength microstrip lines I 222, quarter-wavelength microstrip line II 224; two identical third microstrip lines 225 and fifth microstrip lines 227; two identical fourth microstrip lines 226 and sixth microstrip lines 228; the The characteristic impedance of the third microstrip line 225, the fourth microstrip line 226, the fifth microstrip line 227 and the sixth microstrip line 228 is 100 ohms and the electrical length of the third microstrip line 225 and the fourth microstrip line 226 A difference of 180 degrees, the fifth microstrip line 227 and the sixth microstrip line 228 have a difference of 180 degrees in electrical length; and two identical short-circuit stubs 233; one end of the two short-circuit stubs 233 is respectively connected to a quarter-wavelength microstrip Line I 222 and quarter-wavelength microstrip line II 224, the other end of which is connected to the ground plate 21 through the short-circuit pin 23; Equal output signals; the input signal is passed through the input terminal A, the first microstrip line 221, the quarter-wavelength microstrip line I 222, the third microstrip line 225 and the output terminal B229 to obtain the first output with 0 degree phase shift signal; the input signal passes through the input terminal A, the first microstrip line 221, and a quarter The first wavelength microstrip line I 222, the fourth microstrip line 226 and the output terminal C230 obtain the second output signal with a phase shift of 180 degrees; the input signal passes through the input terminal A, the second microstrip line 223, and the quarter-wavelength microstrip line The strip line II 224, the fifth microstrip line 227 and the output terminal D231 obtain the third output signal with a 90-degree phase shift; the input signal passes through the input terminal A, the second microstrip line 223, and the quarter-wavelength microstrip line II 224 , the sixth microstrip line 228 and the output terminal E232 obtain the fourth output signal with a phase shift of 270 degrees; further, the radiation patch shares the ground plate 21 with the microstrip power division phase-shift feeding network 22; the The characteristic impedance of the short-circuit stub 233 is 70.7 ohms; further, the upper radiation antenna dielectric substrate 1 and the lower feed network dielectric substrate 2 are made of microwave dielectric materials with a thickness of 2 mm and a dielectric constant of 2.65; further, the Distributed capacitance is formed between the antenna main radiation patch 11 and the coupling patch 13, and both are circular patches; the parasitic radiation patch 12 is an arc-shaped patch; two adjacent parasitic radiation patches Slot 14 is formed between 12 and antenna main radiation patch 11; the circular polarization of the L-band broadband circularly polarized microstrip antenna can be adjusted by changing the size and position of the parasitic radiation patch 12 and the size and position of the slot 14 characteristics; further, the size of the coupling patch 13 is adjusted according to the change of the air gap 4 .

The L-band broadband circularly polarized microstrip antenna of the present invention, wherein the radius of the antenna main radiation patch 11 can be 43mm, the arc length of the four parasitic radiation patches 12 can be 8.5mm, and each parasitic radiation patch 12 The distance with the antenna main radiation patch 11 can be 3.5mm, the radius of the metal probe 5 can be 1.45mm, the radius of the coupling patch 13 can be 6.5mm, and the height of the air gap 4 can be 24mm. The present invention can be based on the The size of the coupling patch 13 can be adjusted by changing the air gap 4 above. When the air gap becomes larger, the size of the coupling patch needs to be increased appropriately, and the size and position of the parasitic radiation patch 12 and the size of the slot 14 can also be changed. , position to adjust the circular polarization characteristics of the L-band broadband circularly polarized microstrip antenna. This adjustment process is obtained through HFSS software simulation. The position of the parasitic radiation patch 12 away from the main radiation patch 11 of the antenna is determined by the HFSS software to keep the parasitic The position of the radiation patch 12 from the antenna main radiation patch 11 remains unchanged, the parasitic radiation patch 12 becomes larger, and the circular polarization bandwidth becomes larger; The size and position of the slot 14 are all determined by HFSS software. When the arc length of the four parasitic radiation patches 12 is 8.5 mm, and the distance between each parasitic radiation patch 12 and the antenna main radiation patch 11 is 3.5 mm, the relative The circular polarization bandwidth corresponding to the size of the slot 14 formed between two adjacent parasitic radiation patches 12 and the antenna main radiation patch 11 is the widest, and the first microstrip line of the microstrip power division phase-shifting feed network 22 221 and the second microstrip line 223 have a characteristic impedance of 100 ohms and an electrical length difference of 90 degrees relative to the center frequency of 1600 MHz, which is used to achieve a 90-degree phase shift. The first microstrip line 221 and the second microstrip line 223 respectively pass through four A quarter-wavelength microstrip line I and a quarter-wavelength microstrip line II form a quarter-wavelength impedance converter with the network behind to achieve impedance matching. The third microstrip line 225, the fourth microstrip line 226, The characteristic impedance of the fifth microstrip line 227 and the sixth microstrip line 228 is 100 ohms and the electrical length difference between the third microstrip line 225 and the fourth microstrip line 226 is 180 degrees, the fifth microstrip line 227 and the sixth microstrip line The electrical lengths of the strip lines 228 differ by 180 degrees, and are used to realize a 180-degree phase shift, and the phase shifts of 0 degrees, 90 degrees, 180 degrees, and 270 degrees are sequentially realized through the microstrip power division phase-shift feeding network 22, so as to realize right-hand rotation Circular polarization, when the electrical length of the first microstrip line 221 is λ/8 (relative to the center frequency 1600MHz, the electrical length is 45 degrees) and the electrical length of the second microstrip line 223 is λ*3/8 through simulation calculations, The T-type power splitter has the widest power splitting bandwidth. In addition, a short-circuit branch 233 with a characteristic impedance of 70.7 ohms and an electrical length of λ/4 (relative to the center frequency of 1600MHz) is added to widen the bandwidth of the power splitting ratio and improve The accuracy of the phase shift has been improved; the curve graph of the reflection coefficient of the microstrip antenna of the present invention as shown in Figure 5 varies with frequency, the input of the L-band broadband circularly polarized microstrip antenna End reflection coefficient is all lower than -15dB at 1440MHz-1830MHz, and the input end of antenna is well matched; As shown in Fig. The vertex-axis ratio of the microstrip antenna satisfies that the axial ratio is less than 3dB at 1510MHz-1760MHz, and the circular polarization performance of the antenna is relatively good. The gain of the antenna of the present invention can reach 8dB on the frequency band used, and the impedance bandwidth of the circularly polarized microstrip antenna is relatively wide , the frequency band range of 15dB return loss is 1440MHz-1830MHz, the relative bandwidth is 24%, and has good circular polarization characteristics, the frequency band range of vertex axis ratio is less than 3dB is 1510MHz-1760MHz, and the relative bandwidth is 15%. A kind of L-band wide-band circularly polarized microstrip antenna provided by the present invention, through the radiation patch comprises an antenna main radiation patch placed in the center and four parasitic radiation patches symmetrically distributed around the antenna main radiation patch, The circular polarization bandwidth of the antenna is widened; the metal probe is used to connect the coupling patch and the output end of the microstrip power splitting phase-shifting feed network, and the size of the coupling patch is adjusted according to the change of the air gap, realizing the metal The probe introduces inductance and the coupling patch introduces capacitance compensation, which broadens the impedance bandwidth of the antenna; the microstrip power splitting phase-shifting feed network and the radiation patch are separated by a ground plate, which reduces the parasitic radiation of the feed network The influence on the directivity of the antenna improves the performance of the antenna; the introduction of short-circuit stubs in the microstrip power-splitting phase-shift feed network ensures the accuracy of the power-splitting phase shift of the feed network, and further broadens the impedance bandwidth and circular polarization bandwidth of the antenna; The invention has the advantages of simple structure, low cost, easy tuning, wide impedance bandwidth and circular polarization bandwidth, and is suitable for applications in maritime satellite communication systems and satellite positioning and navigation system terminals.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (9)

1. a L-band broadband circular polarization microstrip antenna, is characterized in that comprising upper strata radiating antenna medium substrate (1) and lower floor's feeding network medium substrate (2); The upper surface of described upper strata radiating antenna medium substrate (1) is printed with radiation patch; Described radiation patch comprises antenna primary radiation paster (11) and four parasitic radiation pasters (12) that are symmetrically distributed in antenna primary radiation paster (11) surrounding of a centering; The lower surface of described upper strata radiating antenna medium substrate (1) is printed with four coupling pasters (13); The upper surface of described lower floor's feeding network medium substrate (2) is provided with ground plate (21), and the lower surface of this lower floor's feeding network medium substrate (2) is printed with the micro-band merit with an input and four outputs and divides phase shift feeding network (22); There is air gap (4) between described upper strata radiating antenna medium substrate (1) and described lower floor's feeding network medium substrate (2); Each described coupling paster (13) divides an output of phase shift feeding network (22) to be connected by a metal probe (5) and micro-band merit; Described micro-band merit divides phase shift feeding network (22) to adopt the micro-band merit of a minute four consisted of T-shaped power splitter to divide phase shift feeding network (22).

2. a kind of L-band broadband circular polarization microstrip antenna according to claim 1, is characterized in that described metal probe (5) through ground plate (21) and insulate mutually with described ground plate (21); Be provided with the protection hole (211) suitable with metal probe (5) on described ground plate (21).

3. a kind of L-band broadband circular polarization microstrip antenna according to claim 1, is characterized in that described micro-band merit divides the input of phase shift feeding network (22) to connect sub-miniature A connectors (6) by 50 ohmage lines (7).

4. a kind of L-band broadband circular polarization microstrip antenna according to claim 1, it is characterized in that described upper strata radiating antenna medium substrate (1) and lower floor's feeding network medium substrate (2) are parallel to each other, and be fixed together to keep by plastic screw (3) air gap (4) had between upper strata radiating antenna medium substrate (1) and described lower floor's feeding network medium substrate (2).

5. a kind of L-band broadband circular polarization microstrip antenna according to claim 1 is characterized in that described micro-band merit divides phase shift feeding network (22) to comprise:

Characteristic impedance is the first microstrip line (221) and the second microstrip line (223) that 100 ohm and electrical length differ 90 degree;

Two identical quarter-wave microstrip line I (222), quarter-wave microstrip line II (224);

Two the 3rd identical microstrip lines (225) and the 5th microstrip line (227);

Two the 4th identical microstrip lines (226) and the 6th microstrip line (228); The characteristic impedance of described the 3rd microstrip line (225), the 4th microstrip line (226), the 5th microstrip line (227) and the 6th microstrip line (228) is that 100 ohm and the 3rd microstrip line (225) differ 180 degree with the electrical length of the 4th microstrip line (226), the 5th microstrip line (227) differs 180 degree with the electrical length of the 6th microstrip line (228);

With two identical short circuit minor matters (233); Two described short circuit minor matters (233) one ends connect respectively quarter-wave microstrip line I (222) and quarter-wave microstrip line II (224), and the other end is connected with ground plate (21) by short circuit pin (23);

Described micro-band merit divides phase shift feeding network (22) to be divided into the equal output signal of four road power by the signal of input A input; Input signal is through input A, the first microstrip line (221), quarter-wave microstrip line I (222), the 3rd microstrip line (225) and output B(229) obtain having the first via output signal of 0 degree phase shift; Input signal is through input A, the first microstrip line (221), quarter-wave microstrip line I (222), the 4th microstrip line (226) and output C(230) obtain having the second tunnel output signal of 180 degree phase shifts; Input signal is through input A, the second microstrip line (223), quarter-wave microstrip line II (224), the 5th microstrip line (227) and output D(231) obtain having the Third Road output signal of 90 degree phase shifts; Input signal is through input A, the second microstrip line (223), quarter-wave microstrip line II (224), the 6th microstrip line (228) and output E(232) obtain having 270 degree phase shift tetra-tunnel output signals.

6. a kind of L-band broadband circular polarization microstrip antenna according to claim 1, is characterized in that described radiation patch and micro-band merit divide phase shift feeding network (22) shared grounding plate (21); The characteristic impedance of described short circuit minor matters (233) is 70.7 ohm.

7. a kind of L-band broadband circular polarization microstrip antenna according to claim 1, is characterized in that it is that the microwave dielectric material that 2mm, dielectric constant are 2.65 is made that described upper strata radiating antenna medium substrate (1) and lower floor's feeding network medium substrate (2) adopt thickness.

8. a kind of L-band broadband circular polarization microstrip antenna according to claim 1, is characterized in that forming distributed capacitance between described antenna primary radiation paster (11) and described coupling paster (13), and be circular patch; Described parasitic radiation paster (12) is circular-arc paster; Form fluting (14) between adjacent two parasitic radiation pasters (12) and antenna primary radiation paster (11); The circular polarization characteristics that L-band broadband circular polarization microstrip antenna is regulated in size, the position of size, position and fluting (14) by changing parasitic radiation paster (12).

9. a kind of L-band broadband circular polarization microstrip antenna according to claim 1, is characterized in that adjusting according to the variation of described air gap (4) size of coupling paster (13).

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