Broadband reconfigurable patch antenna with wide tuning range

Abstract

The invention discloses a broadband reconfigurable patch antenna with a wide tuning range. The broadband reconfigurable patch antenna comprises a pair of face-to-face variable capacitance diode equidirectional loading reconfigurable laminated patch units and a pair of vertical T-shaped structures located between the reconfigurable laminated patch units. According to the invention, a direct current grounding metal column and a pair of vertical T-shaped structures are respectively arranged on the upper side of a variable capacitance diode equidirectional loading reconfigurable laminated patch unit and between the two units; the broadband reconfigurable patch antenna with a wide tuning range is realized by utilizing the weak vertical current of the direct-current grounding metal column, the adjusting effect of the vertical T-shaped structure on common-mode and differential-mode impedance and the high frequency tuning freedom degree of the variable capacitance diode loading the reconfigurable laminated patch in the same direction, and the wide tuning range and the wide instantaneous bandwidth can be considered; and the instantaneous bandwidth is stable and the decoupling degree between units is high.

Description

Technical Field

[0001] This invention relates to a wireless communication device, and more particularly to a broadband reconfigurable patch antenna. Background Technology

[0002] Frequency-reconfigurable patch antennas, which allow the operating frequency to be changed by adjusting the bias voltage of varactor diodes or PIN diodes, are an important component of reconfigurable RF systems. Patch antennas with narrow instantaneous bandwidth require frequent switching of operating states, leading to inefficiency and significantly shortening device lifespan. Wideband reconfigurable patch antennas, with their wider instantaneous bandwidth, reduce the need for state switching. Wide-tuning-range frequency-reconfigurable patch antennas can cover multiple frequency bands, improving the antenna's frequency usability and compatibility, and offering more application scenarios compared to narrow-tuning-range frequency-reconfigurable patch antennas. Therefore, wide-tuning-range broadband reconfigurable patch antennas have significant application value and engineering significance.

[0003] Existing frequency-reconfigurable patch antennas cannot simultaneously satisfy both wide tuning range and wide bandwidth reconfigurability; only those achieving both wide tuning range and wide bandwidth reconfigurable patch antennas are feasible. There are two methods to achieve wide tuning range frequency-reconfigurable patch antennas: The first method involves placing small rectangular metal patches loaded with varactor diodes at the four corners of a metal patch loaded with a slow-wave structure. This utilizes the slow-wave effect to achieve a small-sized wide tuning range frequency-reconfigurable patch antenna array and achieves decoupling between elements, but suffers from narrow instantaneous bandwidth. The second method uses a U-shaped feed structure to excite short stubs and hexagonal metal patches loaded with varactor diodes, achieving a wide tuning range frequency-reconfigurable patch antenna array. However, this method also suffers from narrow instantaneous bandwidth and has a lower degree of decoupling between elements.

[0004] There are two methods to realize a broadband reconfigurable patch antenna: The first method involves connecting an F-type stub loaded with a varactor diode in parallel to the patch's feed structure. This utilizes the controllable radiation null generated by the F-type stub to achieve a broadband frequency-reconfigurable patch antenna. However, this method does not consider the mutual interference during array operation and suffers from problems such as narrow tuning range and insufficient instantaneous bandwidth. The second method uses a short-circuit pin to connect the TM antenna terminated by the varactor diode patch. 10 Module TM 30 While the array can be brought closer together to achieve a reconfigurable patch antenna with a wide instantaneous bandwidth, it does not take into account the mutual influence of the array during operation and has problems such as narrow tuning range, insufficient instantaneous bandwidth, large instantaneous bandwidth fluctuation, and large size.

[0005] Therefore, it is necessary to propose a broadband reconfigurable patch antenna with a wide tuning range that can balance a wide tuning range and a wide instantaneous bandwidth, while maintaining the stability of the instantaneous bandwidth and the decoupling capability between elements. Summary of the Invention

[0006] Purpose of the invention: In view of the above-mentioned prior art, a broadband reconfigurable patch antenna with a wide tuning range is proposed to solve the problem that a wide tuning range and a wide instantaneous bandwidth cannot be achieved at the same time, while maintaining the stability of the instantaneous bandwidth and the decoupling capability between elements during frequency modulation.

[0007] Technical solution: A broadband reconfigurable patch antenna with a wide tuning range, comprising: a top metal structure and device, an upper dielectric substrate, a middle metal structure and device, a lower dielectric substrate, and a metal ground, arranged sequentially from top to bottom, and an air layer between the middle metal structure and device and the upper dielectric substrate; The top-layer metal structure and devices are symmetrically arranged, including two large top-layer rectangular metal patches, two medium top-layer rectangular metal patches, two small top-layer rectangular metal patches, two first varactor diodes, two DC bias pins, and two DC bias pins. The two medium top-layer rectangular metal patches are located inside the two large top-layer rectangular metal patches, and are connected to adjacent medium top-layer rectangular metal patches via first varactor diodes. The two small top-layer rectangular metal patches are located in the middle of the two medium top-layer rectangular metal patches and are symmetrically distributed vertically. The two first DC bias pins are connected to the two large top-layer rectangular metal patches, and the two second DC bias pins are connected to the two medium top-layer rectangular metal patches. The two small top-layer rectangular metal patches are connected to the metal ground via metal pillars. The intermediate layer metal structure and device includes two large rectangular metal patches in the intermediate layer, two medium rectangular metal patches in the intermediate layer, two second varactor diodes, two DC bias three-stage diodes, and two DC bias four-stage diodes. The large rectangular metal patches and medium rectangular metal patches in the intermediate layer are respectively positioned opposite to the top large rectangular metal patch and the top medium rectangular metal patch. The large rectangular metal patches in the intermediate layer are connected to adjacent medium rectangular metal patches in the intermediate layer via second varactor diodes. The two DC bias three-stage diodes are respectively connected to the two large rectangular metal patches in the intermediate layer. The two DC bias four-stage diodes are respectively connected to the two medium rectangular metal patches in the intermediate layer.

[0008] Furthermore, the first DC bias is composed of a short-circuited metal patch and an inductor connected together; the second DC bias is composed of a DC feed patch, a resistor, a short metal strip, and an inductor connected in series; the third DC bias is composed of a short-circuited metal patch and an inductor connected together; the fourth DC bias is composed of a DC feed patch, a resistor, a short metal strip, and an inductor connected in series; wherein, the short-circuited metal patches of the first and third DC biases are connected to the metal ground through a metal post.

[0009] Furthermore, the horizontal length of the top large rectangular metal patch is between 0.21 and 0.27λ0, and the horizontal length of the top middle rectangular metal patch is between 0.052 and 0.067λ0; the vertical lengths of both are the same, between 0.18 and 0.23λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0010] Furthermore, the horizontal length of the small rectangular metal patch is between 0.026 and 0.032λ0, and the vertical length is between 0.044 and 0.056λ0; the edge distance between the small rectangular metal patch and the rectangular metal patch in the top layer is between 0.042 and 0.053λ0, and the center-to-center distance between the two small rectangular metal patches is between 0.18 and 0.23λ0.

[0011] Furthermore, the horizontal length of the large rectangular metal patch in the middle layer is the same as the horizontal length of the large rectangular metal patch in the top layer, and the horizontal length of the rectangular metal patch in the middle layer is between 0.043 and 0.055λ0; the vertical length of the large rectangular metal patch in the middle layer and the rectangular metal patch in the middle layer are the same, both between 0.13 and 0.17λ0.

[0012] Furthermore, the two DC biases are respectively connected to the upper side of the two top-layer large rectangular metal patches, and the distance between the DC biases and the vertical symmetry line is between 0.12 and 0.16λ0; the positions of the two DC biases are aligned vertically with the two DC biases.

[0013] Beneficial Effects: Existing frequency-reconfigurable patch antennas cannot simultaneously satisfy both wide tuning range and wide bandwidth reconfigurability. Furthermore, some designs suffer from large instantaneous bandwidth fluctuations and lack of array decoupling or low decoupling levels. This invention places a DC-grounded metal pillar and a pair of vertical T-structures on the top and middle of a varactor diode-loaded reconfigurable laminated patch element, respectively. Utilizing the weak vertical current of the DC-grounded metal pillar, the adjustment effect of the vertical T-structures on common-mode and differential-mode impedances, and the high degree of freedom in frequency tuning of the varactor diode-loaded reconfigurable laminated patch, a wide-tuning-range broadband reconfigurable patch antenna is achieved. This antenna balances wide tuning range and wide instantaneous bandwidth, with stable instantaneous bandwidth and high degree of decoupling between elements.

[0014] Among them, the DC grounding metal post is connected to the upper side of the large rectangular metal patch of the reconfigurable stacked patch unit through an inductor, and the distance from the center line of the antenna array is between 0.12 and 0.16λ0. On the one hand, it provides a DC circuit for the variable secondary capacitor, and on the other hand, it induces a weak vertical current to improve the decoupling degree between the reconfigurable stacked patch units when the frequency changes.

[0015] A pair of vertical T-shaped structures with a center spacing between 0.18 and 0.23λ0 are composed of small rectangular metal patches and metal pillars, and are symmetrically placed at the center between the antennas. This enables the impedance of the array during common-mode excitation to approach the impedance of the array during differential-mode excitation, realizing the mutual coupling zeros between the units. Furthermore, the mutual coupling zeros move with the operating frequency of the units, realizing the decoupling between the units when the frequency is reconfigurable.

[0016] The reconfigurable stacked patch unit radiator with face-to-face arrangement consists of large rectangular metal patches in the top and middle layers, a varactor diode, and a middle rectangular metal patch in the top and middle layers. By controlling the horizontal length ratio and vertical length ratio of the two patches and the loading position of the varactor diode, the sensitivity of the operating frequency to the varactor diode capacitance value and the two resonant points are ensured, thereby achieving stable broadband operation over a wide tuning range. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of the wide-tuning-range broadband reconfigurable patch antenna of the present invention. Figure 2 This is a schematic diagram of the top-level structure of the wide-tuning-range broadband reconfigurable patch antenna of the present invention; Figure 3 This is a schematic diagram of the intermediate layer structure of the wide tuning range broadband reconfigurable patch antenna of the present invention; Figure 4 The three states of the present invention S Parameter simulation results; Figure 5 The center frequency at 2.52 GHz in state one of the embodiments of the present invention with / without the vertical T-shaped structure. E Face and H Surface simulation radiation pattern; Figure 6 For the embodiment of the present invention with / without the vertical T-shaped structure, state two at the center frequency of 2.7 GHz E Face and H Surface simulation radiation pattern; Figure 7 The center frequency at 3.05 GHz in state three of the embodiments of the present invention with / without the vertical T-shaped structure. E Face and H Surface simulation radiation pattern. Detailed Implementation

[0018] The invention will now be further explained with reference to the accompanying drawings.

[0019] A wide-tuning-range broadband reconfigurable patch antenna, such as Figure 1As shown, it consists of a top metal structure and device 1, an upper dielectric substrate 2, a middle metal structure and device 3, a lower dielectric substrate 4, a metal ground 5, a first metal pillar 6, and a second metal pillar 7. The top metal structure and device 1 is located above the upper dielectric substrate 2, the middle metal structure and device 3 is located in front of the lower dielectric substrate 4, the metal ground 5 is located below the lower dielectric substrate 4, and an air layer is provided between the middle metal structure and device 3 and the upper dielectric substrate 2.

[0020] like Figure 2 As shown, the top-layer metal structure and device 1 consists of two large top-layer rectangular metal patches 101, two medium top-layer rectangular metal patches 102, two small top-layer rectangular metal patches 103, two first varactor diodes 104, two DC bias pins 105, and two DC bias pins 106. The overall structure of the top-layer metal structure and device 1 is symmetrical from left to right. The two medium top-layer rectangular metal patches are located inside the two large top-layer rectangular metal patches 101, and the large top-layer rectangular metal patches 101 are connected to the adjacent medium top-layer rectangular metal patches 102 through the first varactor diodes 104. The two small top-layer rectangular metal patches 103 are located in the middle of the two medium top-layer rectangular metal patches 102 and are symmetrically distributed vertically. The two DC bias pins 105 are connected to the upper side of the two large top-layer rectangular metal patches 101, and the two DC bias pins 106 are connected to the center point of the lower side of the two medium top-layer rectangular metal patches 102. The two small top-layer rectangular metal patches 103 are connected to the metal ground 5 through metal pillars 7.

[0021] The horizontal length of the top-layer large rectangular metal patch 101 is between 0.21 and 0.27λ0, and the horizontal length of the top-layer middle rectangular metal patch 102 is between 0.052 and 0.067λ0; their vertical lengths are the same, both between 0.18 and 0.23λ0, where λ0 is the free-space wavelength corresponding to the center frequency. The horizontal length of the small rectangular metal patch 103 is between 0.026 and 0.032λ0, and its vertical length is between 0.044 and 0.056λ0; the edge distance between the small rectangular metal patch 103 and the top-layer middle rectangular metal patch 102 is between 0.042 and 0.053λ0, and the center-to-center distance between the two small rectangular metal patches 103 is between 0.18 and 0.23λ0. The distance between the DC bias pin 105 and the vertical symmetry line of the structure's center is between 0.12 and 0.16λ0.

[0022] like Figure 3As shown, the intermediate layer metal structure and device 3 comprises two large rectangular metal patches 301, two medium rectangular metal patches 302, two second varactor diodes 303, two DC bias diodes 304, and two DC bias diodes 305. The large rectangular metal patches 301 and medium rectangular metal patches 302 are respectively positioned opposite to the top large rectangular metal patch 101 and the top medium rectangular metal patch 102. That is, the overall structure of the intermediate layer metal structure and device 3 is symmetrical from left to right. The two medium rectangular metal patches 302 are located inside the two large rectangular metal patches 301, and the large rectangular metal patches 301 and the adjacent medium rectangular metal patches 302 are connected through the second varactor diodes 303. Two DC bias three 304s are connected to the upper side of the two intermediate layer large rectangular metal patches 301 respectively, and their positions are aligned vertically with the two DC bias one 105s; two DC bias four 305s are connected to the center point of the lower side of the two intermediate layer middle rectangular metal patches 302 respectively.

[0023] The horizontal length of the large rectangular metal patch 301 in the middle layer is the same as that of the large rectangular metal patch 101 in the top layer. The horizontal length of the rectangular metal patch 302 in the middle layer is between 0.043 and 0.055λ0. The vertical lengths of both are the same, between 0.13 and 0.17λ0.

[0024] DC bias 105 consists of a short-circuited metal patch and an inductor connected together. DC bias 2 106 consists of a DC feed patch, a resistor, a short metal strip, and an inductor connected in series. DC bias 3 304 consists of a short-circuited metal patch and an inductor connected together. DC bias 4 305 consists of a DC feed patch, a resistor, a short metal strip, and an inductor connected in series. The short-circuited metal patches of DC bias 1 105 and DC bias 3 304 are connected to ground 5 via metal post 6.

[0025] In the above structure, the top layer large rectangular metal patch 101, the middle layer large rectangular metal patch 301, the top layer middle rectangular metal patch 102, the middle layer middle rectangular metal patch 302, the first varactor diode 104, the second varactor diode 303, DC bias one 105, DC bias two 106, DC bias three 304, DC bias four 305, the upper dielectric substrate 2, the lower dielectric substrate 4, and the metal ground 5 form a pair of reconfigurable stacked patch units. Two small rectangular metal patches 103 and metal pillars 7 form a pair of vertical T-shaped structures.

[0026] In this invention, the signal is fed in through a coaxial probe, and a wide-range reconfigurable patch antenna with a wide tuning range is achieved through the action of a pair of reconfigurable stacked patch units and a pair of vertical T-shaped structures. During this process, varactor diodes are loaded at similar positions in the same direction on the two layers of the reconfigurable stacked patch units. By controlling the horizontal and vertical length ratios of the two patch layers, as well as the loading position of the varactor diodes, the sensitivity of the operating frequency to the capacitance value of the varactor diodes and the presence of two resonant points are ensured. This results in highly flexible frequency tuning characteristics, facilitating the achievement of a wide tuning range during broadband reconfiguration, and providing stable instantaneous broadband operation.

[0027] The metal pillar connecting DC bias one and DC bias three not only provides a DC circuit for the reconfigurable multilayer surface mount unit, but also utilizes the weak vertical current induced by the metal pillar to improve the decoupling between units when the frequency of the reconfigurable multilayer surface mount unit changes by adjusting the horizontal position of the metal pillar. A pair of vertical T-structures, when the frequency of the reconfigurable unit changes, can bring the impedance during common-mode excitation of the array closer to the impedance during differential-mode excitation of the array, achieving mutual coupling zeros between units. Furthermore, these mutual coupling zeros shift with the unit's operating frequency, achieving decoupling between units during frequency reconfiguration. Therefore, the combination of the metal pillar and the vertical T-structure enables high decoupling between broadband reconfigurable units over a wide tuning range and also provides pattern correction capabilities.

[0028] The substrate used in this embodiment is Rogers RO4003C, the varactor diode is SMV2201-040LF, and the array size is 0.89λ0 × 0.30λ0 × 0.11λ0. The horizontal length of the top-layer large rectangular metal patch 101 is 0.23λ0, and the horizontal length of the top-layer middle rectangular metal patch 102 is 0.058λ0; both have the same vertical length of 0.2λ0. The horizontal length of the small rectangular metal patch 103 is 0.028λ0, and the vertical length is 0.06λ0; the edge distance between the small rectangular metal patch 103 and the top-layer middle rectangular metal patch 102 is 0.0087λ0, and the center-to-center distance between the two small rectangular metal patches 103 is 0.2λ0. The distance between the DC bias -105 and the central symmetry line of the structure is 0.14λ0. The horizontal length of the rectangular metal patch 302 in the intermediate layer is 0.048λ0, and the vertical length is 0.15λ0.

[0029] Figure 4 The simulation results for the antenna in three states in this embodiment are listed. SThe parameter response curves are as follows: State 1: Cv = 2.1 pF; State 2: Cv = 1.2 pF; State 3: Cv = 0.23 pF. The corresponding matching frequency ranges for the three states are 2.41 GHz ~ 2.87 GHz, 2.56 GHz ~ 3.07 GHz, and 2.85 GHz ~ 3.37 GHz, respectively; that is, the relative bandwidths can reach 17.4%, 17.9%, and 17.6%, respectively, achieving broadband operation in each state. The overall -10 dB adjustable operating frequency range covers a relative matching frequency range of up to 33.2%. Simultaneously, the mutual coupling is below -25.5 dB during the overall frequency adjustment process, indicating that this invention achieves a wide tuning range and broadband reconfigurability while also possessing good decoupling performance.

[0030] Figure 5 The center frequency in three states with / without / without vertical T-structure E noodle, H Surface orientation diagram, from Figure 5 It can be seen that after adding the vertical T-shaped structure E The surface radiation pattern shows a significant improvement, indicating that it has radiation pattern decoupling capability.

[0031] Compared with the prior art, the wide tuning range broadband reconfigurable patch antenna of the present invention has the advantages of balancing wide tuning range and broadband reconfigurability, and also has stable instantaneous bandwidth and high degree of decoupling between elements.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A broadband reconfigurable patch antenna with a wide tuning range, characterized in that, include: It includes a top metal structure and device (1), an upper dielectric substrate (2), a middle metal structure and device (3), a lower dielectric substrate (4), and a metal ground (5) arranged sequentially from top to bottom, and an air layer is provided between the middle metal structure and device (3) and the upper dielectric substrate (2); The top-layer metal structure and device (1) is a left-right symmetrical structure, including two top-layer large rectangular metal patches (101), two top-layer medium rectangular metal patches (102), two small rectangular metal patches (103), two first varactor diodes (104), two DC bias one (105), and two DC bias two (106); wherein, the two top-layer medium rectangular metal patches are located inside the two top-layer large rectangular metal patches (101), and the top-layer large rectangular metal patches (101) are adjacent to the top-layer medium rectangular metal patches (106). The metal patch (102) is connected through the first varactor diode (104); two small rectangular metal patches (103) are located in the middle of the two top rectangular metal patches (102) and are symmetrically distributed vertically; two DC bias one (105) are respectively connected to the two top large rectangular metal patches (101), and two DC bias two (106) are respectively connected to the two top middle rectangular metal patches (102); the two small rectangular metal patches (103) are respectively connected to the metal ground (5) through metal pillar two (7); The intermediate layer metal structure and device (3) includes two intermediate layer large rectangular metal patches (301), two intermediate layer middle rectangular metal patches (302), two second varactor diodes (303), two DC bias three (304) and two DC bias four (305); wherein, the intermediate layer large rectangular metal patches (301) and the intermediate layer middle rectangular metal patches (302) are respectively arranged opposite to the top layer large rectangular metal patch (101) and the top layer middle rectangular metal patch (102); the intermediate layer large rectangular metal patch (301) and the adjacent intermediate layer middle rectangular metal patch (302) are connected through the second varactor diodes (303); the two DC bias three (304) are respectively connected to the two intermediate layer large rectangular metal patches (301); the two DC bias four (305) are respectively connected to the two intermediate layer middle rectangular metal patches (302).

2. The broadband reconfigurable patch antenna with a wide tuning range according to claim 1, characterized in that, The DC bias one (105) is composed of a short-circuit metal patch and an inductor connected together; the DC bias two (106) is composed of a DC feed patch, a resistor, a short metal strip and an inductor connected in series; the DC bias three (304) is composed of a short-circuit metal patch and an inductor connected together; the DC bias four (305) is composed of a DC feed patch, a resistor, a short metal strip and an inductor connected in series; wherein, the short-circuit metal patch of the DC bias one (105) and the DC bias three (304) is connected to the metal ground (5) through a metal post one (6).

3. The broadband reconfigurable patch antenna with a wide tuning range according to claim 1, characterized in that, The horizontal length of the top large rectangular metal patch (101) is between 0.21 and 0.27λ0, and the horizontal length of the top middle rectangular metal patch (102) is between 0.052 and 0.067λ0; the vertical lengths of both are the same, both between 0.18 and 0.23λ0, where λ0 is the free space wavelength corresponding to the center frequency.

4. The broadband reconfigurable patch antenna with a wide tuning range according to claim 3, characterized in that, The horizontal length of the small rectangular metal patch (103) is between 0.026 and 0.032λ0, and the vertical length is between 0.044 and 0.056λ0; the edge distance between the small rectangular metal patch (103) and the top rectangular metal patch (102) is between 0.042 and 0.053λ0, and the center distance between the two small rectangular metal patches (103) is between 0.18 and 0.23λ0.

5. The broadband reconfigurable patch antenna with a wide tuning range according to claim 3, characterized in that, The horizontal length of the large rectangular metal patch (301) in the middle layer is the same as that of the large rectangular metal patch (101) in the top layer. The horizontal length of the rectangular metal patch (302) in the middle layer is between 0.043 and 0.055λ0. The vertical lengths of the large rectangular metal patch (301) and the rectangular metal patch (302) in the middle layer are the same, both between 0.13 and 0.17λ0.

6. The broadband reconfigurable patch antenna with a wide tuning range according to claim 3, characterized in that, The two DC biases (105) are connected to the upper sides of the two top rectangular metal patches (101) respectively. The distance between the DC biases (105) and the vertical symmetry line is between 0.12 and 0.16λ0. The positions of the two DC biases (304) are aligned vertically with the two DC biases (105).

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