High Isolation Wideband Dual-Polarized Dielectric Patch Antenna for Full-Duplex Communication

Abstract

The present invention discloses a high-isolation broadband dual-polarized dielectric patch antenna for full-duplex communication. The antenna consists of a rectangular dielectric patch with a pair of slots etched on its edge and two layers of substrates. The dielectric patch is placed on the top substrate and excited by three ports. In the X-polarization direction, a single port is used to excite the fundamental mode TM 10 mode and the higher-order mode TE 12 mode for broadband transmitter operation. For the Y-polarization direction, a differential feeding structure is adopted to excite the degenerate TM 01 mode and the anti-phase TM 02 mode for broadband receiver operation. A metal floor is placed between the two layers of substrates, and two sets of slots are etched on it for aperture coupling between the dielectric patch resonator and the metal microstrip line located at the bottom of the lower substrate.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and particularly to a high-isolation broadband dual-polarized dielectric patch antenna for full-duplex communication. Background Art

[0002] The currently available spectrum resources are very limited. With the rapid development of wireless communication, these spectrum resources have become increasingly crowded. How to improve the spectrum utilization rate has become a key research topic. At present, most wireless communication systems have terminals that transmit and receive signals (such as base stations, relays, and mobile terminals). Most of these communication systems are time-division or frequency-division duplex communication systems, that is, these terminals do not transmit and receive signals at the same time or frequency band. Different from this, a simultaneous and co-frequency full-duplex communication system can ensure that the transmitted signal and the received signal are completed simultaneously and at the same frequency, thereby doubling the transmission speed of the data stream, the communication capacity of the wireless communication system, and the spectrum utilization rate. As the front end of the full-duplex system, using a high-isolation antenna is the key to achieving high-quality communication in engineering applications. Technologies such as antenna separation, near-field cancellation, parasitic structures, and placing absorbers between antennas can all achieve high isolation. These technologies usually use multiple separate antennas or large and complex antenna structures, resulting in a large physical size.

[0003] Dual-polarized antennas have received extensive attention due to the advantages of miniaturization by using a shared radiation aperture and the natural isolation between orthogonal polarizations. To meet the high-isolation requirements of full-duplex applications, various low-profile differentially-fed dual-polarized antennas have been widely developed. However, all of the above designs are based on metal, with a single-mode operating mode and a narrow operating bandwidth, which are not suitable for the application background of high speed and large capacity. Recently, a new type of feeding structure - magnetic loop can achieve bandwidth enhancement. An antenna composed of magnetic feeding and electric feeding has achieved a relatively wide bandwidth, but the port isolation is only over 20 dB. In addition, by superimposing a metasurface structure on the feeding patch, a bandwidth of 28.4% has been achieved. However, the high profile is still a limiting factor, and the complexity also increases with the introduction of the overhead structure.

[0004] Dielectric resonator antennas are also suitable for dual-polarization designs and have been widely studied in the past few decades. Dielectric patch antennas are the best compromise between dielectric resonator antennas and microstrip patch antennas in terms of shape, efficiency, and gain. They are developed to overcome the limitations of traditional dielectric resonator antennas, such as high profile and poor gain. More importantly, the higher-order modes of dielectric patch resonators can achieve bandwidth expansion, which benefits from the multimode characteristics inherited from dielectric resonators. In the literature S.-C. Tang, X.-Y. Wang, W.-W. Yang and J.-X. Chen, “Wideband low-profile dielectric patch antenna and array with anisotropic property,” IEEE Trans. Antennas Propag., vol. 68, no. 5, pp. 4091-4096, May. 2020., by introducing a silver-plated slot, the higher-order mode can be shifted down to be close to the fundamental mode, thus achieving bandwidth expansion for linearly polarized antennas. As far as we know, the design of dual-polarized dielectric patch antennas is rare. The dual-polarized dielectric patch antenna in the literature X.-Y. Wang, S.-C. Tang and J.-X. Chen, “Differential-fed dual-polarized dielectric patch antenna with gain enhancement based on higher order modes,” IEEE Antennas Wireless Propag. Lett., vol. 19, no. 3, pp. 502-506, March. 2020. uses differential feeding technology to achieve a high isolation of 34 dB. Although the introduced ground rod can combine with the higher-order modes of the dielectric patch, the bandwidth can only be expanded to 4.88%. There is currently no dual-polarized dielectric patch antenna that simultaneously has broadband performance and high isolation. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned defects of the prior art and propose a high-isolation broadband dual-polarized dielectric patch antenna for full-duplex communication. The antenna makes full use of the multimode characteristics of the dielectric patch resonator. By adjusting the aspect ratio of the dielectric patch, the higher-order TE 12 mode can be reduced to be close to the fundamental TM 10 mode, thereby achieving broadband performance in the X-polarization direction. At the same time, by etching a pair of slots on the edge of the dielectric patch and an improved coupling slot, the upward shift of the TM 01 mode and the inverted TM 02The downward movement of the mode realizes the broadband performance in the Y-polarization direction. High isolation of the antenna is achieved through a differential feeding scheme.

[0006] To achieve the object of the present invention, the present invention proposes a high-isolation broadband dual-polarized dielectric patch antenna for full-duplex communication. The antenna consists of a rectangular dielectric patch with a pair of slots etched on its edge and two layers of substrates. The dielectric patch is placed on the top substrate and excited by three ports. In the X-polarization direction, a single port is used to excite the fundamental mode TM 10 mode and the higher-order mode TE 12 mode for broadband transmitter (Tx) operation. For the Y-polarization direction, a differential feeding structure is adopted, and a pair of differential input ports are used to excite the degenerate TM 01 mode and the inverted TM 02 mode for broadband receiver (Rx) operation. A metal ground reflection floor is placed between the two layers of substrates, and two groups of slots are etched on it for aperture coupling between the dielectric patch resonator and the metal microstrip line located at the bottom of the lower substrate. Among them, the coupling slot corresponding to the single-feed input feeder is used for aperture coupling in the X-polarization direction, and the coupling slot corresponding to the differential input feeder consists of a pair of back-to-back U-shaped slots for aperture coupling in the Y-polarization direction.

[0007] High isolation of the antenna is achieved through a differential feeding scheme in the present invention. By adjusting the aspect ratio of the dielectric patch, the higher-order TE 12 mode can be reduced to be close to the fundamental mode TM 10 mode, thereby realizing the broadband performance in the X-polarization direction. At the same time, through a pair of slots etched on the edge of the dielectric patch and the improved U-shaped coupling slots on the metal reflection floor, the upward movement of the TM 01 mode and the downward movement of the inverted TM 02 mode are respectively realized, thereby realizing the broadband performance in the Y-polarization direction.

[0008] The antenna has the advantages of wide bandwidth, high isolation, low profile, simple structure, etc., and has broad application prospects in full-duplex systems. Brief Description of the Drawings

[0009] The present invention will be further described below with reference to the accompanying drawings.

[0010] Figure 1 is a perspective view of the broadband dual-polarized dielectric patch antenna of the present invention.

[0011] Figure 2 is a schematic structural diagram of the broadband dual-polarized dielectric patch antenna of the present invention.

[0012] Figure 3 is the simulated return loss and port isolation of the broadband dual-polarized dielectric patch antenna of the present invention.

[0013] Figure 4 is the simulated gain of the two ports of the broadband dual-polarized dielectric patch antenna of the present invention.

[0014] Figure 5 is the simulated radiation pattern of the single-feed input port of the broadband dual-polarized dielectric patch antenna of the present invention at 5.29 GHz.

[0015] Figure 6 is the simulated radiation pattern of the differential input port of the broadband dual-polarized dielectric patch antenna of the present invention at 5.2 GHz.

[0016] The reference numerals in the figure are illustrated as follows:

[0017] 1 - dielectric patch, 2 - groove, 3 - top substrate, 4 - metal reflector floor, 5 - straight coupling slot, 6 - U-shaped coupling slot, 7 - bottom substrate, 8 - single-feed microstrip feeder, 9 - differential microstrip feeder. Detailed implementation manners

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Refer to Figure 1 is a schematic diagram of the high-isolation broadband dual-polarized dielectric patch antenna for full-duplex communication implemented by the present invention. The dual-polarized dielectric patch antenna implemented by the present invention includes a bottom substrate 7, a metal reflector floor 4, a top substrate 3, and a dielectric patch 1 stacked in sequence from bottom to top. The dielectric patch 1 is a rectangular dielectric patch, which is glued to the center of the top substrate 3, and its short side is located in the X polarization direction. A pair of grooves 2 are etched on the edge of the short side of the dielectric patch 1, and the grooves 2 are symmetric about the vertical bisecting plane of the dielectric patch 1. The lower surface of the bottom substrate 7 is provided with a single-feed microstrip feeder 8 and a differential microstrip feeder 9. Both the single-feed microstrip feeder 8 and the differential microstrip feeder 9 are composed of a 50Ω transmission line near the input port and a section of λ / 4 impedance transformation line for matching. The 50Ω transmission line is connected to the signal input port. The bottom substrate 7 is a double-sided printed circuit board. The top layer of the double-sided printed circuit board is the metal reflector floor 4, and the bottom layer is the single-feed microstrip feeder 8 and the differential microstrip feeder 9. The single-feed microstrip feeder 8 is arranged along the X polarization direction, and the differential microstrip feeder 9 is arranged along the Y polarization direction. Two groups of coupling slots are etched on the metal reflector floor 4: the first group of coupling slots is a straight coupling slot 5, and the straight coupling slot 5 is located at the center of the metal reflector floor and is arranged along the Y polarization direction (the straight coupling slot 5 is orthogonal to the single-feed microstrip feeder 8); the second group of coupling slots is a pair of back-to-back U-shaped coupling slots 6 that are respectively arranged at both ends of the straight coupling slot 5 and are orthogonal to the differential microstrip feeder 9.

[0020] The lower surface edge of the bottom substrate 7 is also provided with a single-feed input port S1 connected to the single-feed microstrip feeder 8, and differential input ports S2 + and S2 - connected to the differential microstrip feeder 9.

[0021] In the X - polarization direction, the fundamental mode TM 10 mode and the higher - order mode TE 12 mode are excited by the single - feed microstrip feeder 8 for broadband transmitter operation; in the Y - polarization direction, the degenerate TM 01 mode and the inverted - phase TM 02 mode are excited by the differential microstrip feeder 9 for broadband receiver operation.

[0022] In the embodiments of the present invention, the dimensions of each part of the antenna are optimized. The specific parameters of the antenna are shown in the following table:

[0023] Parameter <![CDATA[L g > <![CDATA[W g > h <![CDATA[l d > <![CDATA[w d > <![CDATA[h d > <![CDATA[l c > <![CDATA[w c > Value (mm) 55 60 0.813 36.8 26 1.5 8 4 Parameter <![CDATA[l s1 > <![CDATA[w s1 > <![CDATA[l s2 > <![CDATA[l s3 > <![CDATA[w s2 > <![CDATA[d s > <![CDATA[w f1 > <![CDATA[w f2 > Value (mm) 8.3 0.9 6.9 2.2 1 20 1.5 1.4

[0024] In the table, h is the height of the top substrate 3 and the bottom substrate 7, l d is the length of the dielectric patch, w d is the width of the dielectric patch, h d is the thickness of the dielectric substrate, l c is the length of the groove, w c is the width of the groove, l s1 is the length of the straight - line coupling slot 5, w s1 is the width of the straight - line coupling slot 5, l s2 and l s3 are the lengths of the U - shaped coupling slot 6, w s2 is the width of the U - shaped coupling slot 6, d s is the distance between the coupling slots of the U - shaped coupling slot 6.

[0025] The substrate used in the design is Rogers RO4003, with a dielectric constant of ε r = 3.38 and a loss tangent of tanδ = 2.7×10 -3 , and the volume of the top substrate 3 and the bottom substrate 7 is L g ×W g ×h. The bottom substrate 7 is a double - sided printed circuit board. The upper surface of the double - sided printed circuit board 7 is the metal reflection ground 4, and the lower surface is the microstrip feeder.

[0026] Figure 3 Shown here are the simulated reflection coefficients and inter - port isolation of the broadband dual - polarization dielectric patch antenna in this example. The bandwidth of the single - feed input port S1 is 25.2%, and the bandwidth of the differential input port S2 is 17%. The inter - port isolation is greater than 52 dB.

[0027] Figure 4 Shown here are the simulated gains of the two ports of the broadband dual - polarization dielectric patch antenna in this example. The maximum in - band gain of the single - feed input port S1 is 8.4, and the maximum in - band gain of the differential input port S2 is 7.6 dBi.

[0028] Figure 5 Figure 6 The simulated E-plane and H-plane radiation patterns for the single-feed input port S1 and differential input port S2 show that: the cross-polarization of the antenna is at least 20 dB lower than the main polarization, and it can be inferred that the antenna can exhibit a stable broadside radiation pattern throughout the entire frequency tuning range.

[0029] In addition to the above embodiments, the present invention may have other embodiments. Any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A high isolation broadband dual-polarized dielectric patch antenna for full-duplex communication, comprising a bottom substrate (7), a metal reflection floor (4), a top substrate (3) and a dielectric patch (1) stacked in sequence from bottom to top, characterized in that: On the lower surface of the underlying substrate (7), a single-feed microstrip feeder (8) along the X polarization direction and a pair of differential microstrip feeders (9) along the Y polarization direction are provided. Coupling slots (5, 6) orthogonal to the corresponding microstrip feeders are formed in the metal reflection floor (4); in the X polarization direction, the fundamental mode TM 10 mode and the higher-order mode TE 12 mode are excited through the single-feed microstrip feeder (8) for the operation of a broadband transmitter; in the Y polarization direction, the degenerate TM 01 mode and the anti-phase TM 02 mode are excited through the differential microstrip feeders (9) for the operation of a broadband receiver; The dielectric patch (1) is a rectangular dielectric patch, and a pair of grooves (2) are symmetrically arranged on its vertical middle plane. The coupling slots (5, 6) include a linear coupling slot (5) located at the center of the metal reflection floor (4) and orthogonal to the single-feed microstrip feeder (8), and a pair of back-to-back U-shaped coupling slots (6) respectively arranged at both ends of the linear coupling slot (5) and orthogonal to the differential microstrip feeder (9).

2. The high isolation broadband dual-polarized dielectric patch antenna for full-duplex communication according to claim 1, wherein: The short side of the dielectric patch (1) is in the X polarization direction, and the groove (2) is opened on one side of the short side of the dielectric patch (1).

3. The high isolation broadband dual-polarized dielectric patch antenna for full-duplex communication according to claim 1, wherein: On the lower surface edge of the bottom substrate (7), a single-feed input port (S1) connected to the single-feed microstrip feeder (8) and differential input ports (S2+, S2-) connected to the differential microstrip feeder (9) are further provided.

4. The high isolation broadband dual-polarized dielectric patch antenna for full-duplex communication according to claim 3, wherein: The single-feed microstrip feeder (8) and the differential microstrip feeder (9) are composed of a 50Ω transmission line and a section of λ / 4 impedance transformation line for matching, and the 50Ω transmission line is connected to the signal input port.

5. The high isolation broadband dual-polarized dielectric patch antenna for full-duplex communication according to claim 1, characterized in that: The bottom substrate (7) is a double-sided printed circuit board. The top layer of the double-sided printed circuit board is the metal reflection floor (4), and the bottom layer is the single-feed microstrip feeder (8) and the differential microstrip feeder (9).

6. The high isolation broadband dual-polarized dielectric patch antenna for full-duplex communication according to claim 1, wherein: The dielectric patch (1) is adhered to the center of the upper surface of the top substrate (3) by glue.

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