CN106410376A - E-band miniature plate antenna and simultaneous cofrequency diplexer composed of same E-band miniature plat antenna - Google Patents

Abstract

The present invention provides a kind of E-band miniaturized planar antenna and the same-frequency duplexer constituted thereof at the same time. The E-band miniaturized planar antenna installs four small radiating units equidistantly rectangularly arranged on a large radiating unit. The large radiating unit is connected to the feeding waveguide through the coupling slot; two E-band miniaturized planar antennas are used as the transmitting antenna and the receiving antenna, and are integrated in parallel in the same-frequency duplexer, and the polarization forms of the transmitting antenna and the receiving antenna are orthogonal . The antenna of the invention adopts a miniaturized flat panel antenna, which is easy to integrate and does not increase the complexity of the system. The duplex system of the present invention improves the integration degree of the system, reduces the complexity of the system composition, and can effectively improve the utilization rate of the spectrum resources of the system.

Description

An E-band miniaturized planar antenna and the simultaneous co-frequency duplexer it constitutes

technical field

The invention belongs to the field of millimeter-wave large-capacity communication, and relates to an E-band panel antenna based on a parallel-feed multilayer waveguide slot array and a simultaneous co-frequency duplexer based on cross-polarization cancellation.

Background technique

With the increasing saturation of spectrum utilization and increasing pressure on communication services, the demand for new frequency bands and high bandwidth is becoming stronger and stronger. Millimeter wave communication has gradually matured and been widely used in both military and civilian fields. E-band refers to the higher millimeter-wave frequency bands that work in the uplink and downlink at 71-76GHz and 81-86GHz respectively. This frequency band has a total bandwidth of 10GHz, which can bear a huge communication capacity business. At present, E-band communication has been widely used in the backhaul link of the LTE core network. With high-order modulation methods, such as 256QAM, the air interface transmission rate of more than 3Gbps can be achieved. With the gradual development of high-power devices, E-band will have a wider range of application scenarios in the future, such as inter-satellite, satellite-ground links, and high-capacity real-time intelligence reconnaissance and other fields.

In order to overcome the influence of atmospheric attenuation and rain attenuation, the high-gain antenna is the core device for E-band applications. At present, most mature products use parabolic antennas, but such antennas have a large cross-section and are difficult to integrate into the system. The use of planar arrays will greatly reduce the antenna profile, and some scholars have studied the use of SIW or GapWaveguid to make planar arrays. However, since these two forms are both semi-open feeder networks, and the dielectric loss in the high-frequency band is relatively large, their efficiency is limited to a certain extent. With the maturity of the injection molding and electroplating process, the processing accuracy of the waveguide array has been gradually improved. In the future, the waveguide slot array using the injection molding and electroplating process will have the huge advantages of low profile and light weight. The traditional waveguide slot array adopts the form of series feed, but its amplitude and phase balance design is relatively complicated. In comparison, adopting the parallel-feed design can greatly reduce the design difficulty, and it is easy to ensure the amplitude and phase balance of the radiation unit. Due to the extremely high frequency band of the E-band, the size of its radiating elements is relatively small. In order to ensure the tight coupling between the elements, the distance between them needs to be extremely small. The structure of the traditional parallel-fed unit is shown in Figure 1. The use of this traditional parallel-fed unit will cause the interference of the feed network structure, so the array cannot be realized.

In order to fundamentally improve the transmission capacity, it is necessary to improve the spectrum utilization rate of the system. Traditional methods use higher modulation methods, such as 1024QAM, 2048QAM, or use methods such as non-orthogonal signals to improve spectral efficiency. However, these methods require a higher demodulation threshold to a certain extent, which limits the communication distance of the system or requires higher transmission power. In contrast, the simultaneous same-frequency duplexing method using radio frequency cancellation is a means to effectively improve spectrum utilization without increasing the pressure on the digital signal processing part.

The traditional duplexer forms are mainly divided into frequency division duplex and time division duplex. The duplexer of frequency division duplexing consists of a transceiver channel filter and a T-shaped head. Since a wide guard interval is reserved between the transceiver frequency bands, it can be designed to ensure that the transmit and receive passbands fall within each other's stopbands, thereby providing higher transceiver isolation. However, this form needs to provide different frequency bands for the receiving and transmitting channels, thus causing a great waste of spectrum. The time-division duplex transceiver channel uses the same frequency band, and generally adopts the form of a circulator to provide a combination, so it has a high spectrum utilization rate. However, in order to achieve a large bandwidth, the isolation of the circulator is often limited, generally only about 20dB. Therefore, it is necessary to add a group of switches in the receiving channel to ensure the isolation between sending and receiving. But when the switch is turned on, it will bring great loss to the receiving link. At this time, the signal cannot be received normally, and the signal can only be transmitted. So time division duplex is not strictly a form of full duplex. Simultaneous co-frequency duplexing based on radio frequency cancellation can effectively utilize spectrum resources and realize full-duplex communication in the same frequency band.

Contents of the invention

In order to overcome the deficiencies of the prior art, the present invention provides an E-band miniaturized planar antenna, which is easy to integrate.

The technical solution adopted by the present invention to solve the technical problems is: a kind of E-band miniaturized panel antenna, including four small radiation units and a large radiation unit; the large radiation unit is a rectangular unit, through the rectangular unit middle part The coupling slot is connected to the feed waveguide located on the lower side of the rectangular unit; four identical small radiating units are all rectangular, connected to the upper side of the large radiating unit, forming a 2*2 equidistant rectangular array.

A perturbation slot with a rectangular horizontal section is opened at the center of the four sides of the large radiation unit, and the perturbation slot runs through the upper and lower surfaces of the large radiation unit.

The length of the long side of the small radiation unit is half the wavelength of the working frequency point, and the length of the short side does not exceed the half wavelength of the working frequency point; the period between each small radiation unit does not exceed the wavelength of the working frequency point; the thickness of the small radiation unit does not exceed 1mm; the length of the long side of the large radiation unit is one working wavelength, and the width does not exceed the half-wavelength of the working frequency; the thickness of the large radiation unit does not exceed 1mm; the width and depth of the perturbation gap do not exceed 1mm.

The coupling slot between the feeding waveguide and the large radiation unit is a rectangular slot; the length of the coupling slot is half of the wavelength of the working frequency point, and the width of the coupling slot is not more than a quarter of the wavelength of the working frequency point.

The present invention also provides a simultaneous co-frequency duplexer, using two E-band miniaturized planar antennas as the transmitting antenna and receiving antenna, integrated in parallel inside the simultaneous co-frequency duplexer, the polarization form of the transmitting antenna and the receiving antenna Orthogonal, the feeding port of the transmitting antenna extends to the interface of the simultaneous co-frequency duplexer to form a transmitting port, and the feeding port of the receiving antenna extends to the interface of the simultaneous co-frequency duplexer to form a receiving port.

The beneficial effects of the present invention are: the present invention utilizes the polarization isolation characteristics and inherent space isolation characteristics of the two transmitting and receiving antennas to form a duplex system. The antenna adopts a miniaturized flat panel antenna, which is easy to integrate. Since the directional antenna is a necessary device for millimeter wave communication and cannot be replaced, the use of antennas to form a duplex system does not increase the complexity of the system. The invention utilizes the isolation characteristic of the antenna to replace the traditional frequency division and time division duplex system. This new duplex system does not need to add an additional duplexer, which improves the integration of the system and reduces the complexity of the system composition. At the same time, compared with the frequency division duplex system using the protection frequency band to provide transceiver isolation, the present invention can effectively improve the utilization rate of the system to spectrum resources; compared with the time division duplex system using the switch group to provide transceiver isolation is a half-duplex form , the present invention provides a full-duplex mode for efficiently utilizing spectrum resources.

Description of drawings

Fig. 1 is a schematic diagram of a conventional parallel-fed waveguide slot unit, wherein (a) is a top view, (b) is a plan view, 1 represents a coupling slot, 2 represents a radiation unit, and 3 represents a feed waveguide.

Fig. 2 is a schematic diagram of the multilayer waveguide slot unit proposed by the present invention, wherein (a) is a top view, (b) is a plan view, 1 represents a coupling slot, 3 represents a feed waveguide, 4 represents a small radiation unit on the upper layer, and 5 represents a lower layer Large radiating unit, 6 represents the perturbation slot.

Fig. 3 is a schematic diagram showing the comparison between the return loss of the feed port of the unit proposed by the present invention and the return loss without introducing perturbation.

4 is a composition block diagram of a simultaneous co-frequency duplexer proposed by the present invention, 7 represents a transmitting antenna, 8 represents a receiving antenna, 9 represents a simultaneous co-frequency duplexer, 10 represents a transmitting port, and 11 represents a receiving port.

Fig. 5 is a model diagram of a 4*4 linear array composed of units proposed by the present invention, wherein (a) is a front view, and (b) is a rear view.

Figure 6 is a schematic diagram of the structure of the T-shaped joint on the E plane, 12 represents 1 port, 13 represents 2 ports, 14 represents 3 ports, and 15 represents the matching structure.

Figure 7 is a schematic diagram of the performance of the T-section port on the E plane.

Fig. 8 is a schematic diagram of the return loss of the array feeding port of the present invention.

Fig. 9 is a diagram of the array gain pattern of the present invention.

Fig. 10 is a schematic structural diagram of a simultaneous co-frequency duplexer designed in the present invention, wherein (a) is a front view, (b) is a rear view, 10 represents a transmitting port, and 11 represents a receiving port.

FIG. 11 is a schematic diagram of the isolation degree of a simultaneous co-frequency duplexer designed in the present invention.

Figure 12 is an example diagram of the assembly of the duplexer and the system of the present invention, 9 represents the duplexer, 16 represents the housing of the complete machine, 17 represents the transceiver channel circuit, and 18 represents the radome.

Fig. 13 is a structural dimension diagram of the radiation unit of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, and the present invention includes but not limited to the following embodiments.

The present invention designs a multi-layer waveguide slot array based on parallel feeding, and the unit structure is shown in FIG. 2 . In order to make the feed network easy to realize, it is necessary to increase the size of the unit, but blindly increasing the unit size will cause the resonance point to shift to the low frequency, so that the matching in the working frequency band cannot be achieved. In addition, an excessively large cell size will cause severe distortion of the pattern. In order to overcome these problems, the present invention designs a multilayer radiating unit structure in which four small radiating units are parasitic on one large radiating unit. This structure can effectively ensure impedance matching within the working bandwidth and avoid pattern distortion. The large radiating unit is a rectangular unit located in the lower layer and connected to the feeding waveguide through the coupling slot. The four small radiating units are located on the upper floor, all of which are rectangular, with exactly the same dimensions, forming a 2*2 equidistant rectangular array, which is directly connected to the large radiating unit on the lower floor. In order to expand the standing wave ratio bandwidth of the unit, the invention introduces perturbation around the unit, thereby improving the surface current distribution and realizing impedance matching in a wider frequency band. In the present invention, a rectangular slit is formed at the center of the four sides of the large radiation unit to form a perturbation, and the length of the slit is the same as the thickness of the large radiation unit. The comparison of the return loss of the feed port with and without perturbation is shown in Figure 3. Using this unit to form a two-dimensional array can provide a low-profile, easy-to-integrate panel antenna. The number of elements forming the array depends on the antenna gain required by the link budget. The more elements forming the array, the higher the gain of the antenna and the larger the size of the antenna.

According to the basic theory of the slot antenna, when designing a small radiation unit, the length of the unit is half the wavelength of the working frequency, and the width of the unit is related to the required bandwidth. The wider the width, the wider the bandwidth, but it does not exceed the half wavelength of the working frequency. The period between the small radiating units (the distance between the centers of adjacent small radiating units) does not exceed one wavelength, so as to ensure the tight coupling between the units. The thickness of the small radiation unit affects the matching of standing wave ratio, but it is controlled within 1mm to ensure easy processing. The length of the large radiation unit in the lower layer is one working wavelength, the width is related to the bandwidth, but not more than one working wavelength, and the thickness is controlled within 1mm. The narrower the width and the deeper the perturbation slit on the large radiation unit, the stronger its influence on the surface current, and the width and depth are both less than 1 mm. The coupling gap between the feeding waveguide and the lower radiation unit is a rectangular gap, and the smaller the thickness of the gap, the stronger the coupling. The length of the coupling gap is related to the working frequency point, which is half of the wavelength of the working frequency point. The width of the coupling gap is related to the bandwidth, but not more than a quarter of the wavelength of the operating frequency point.

The invention utilizes the polarization characteristics and space isolation characteristics of the antenna, and designs a new type of simultaneous and co-frequency duplexer with the advantages of low profile and easy integration of the flat panel antenna, which can effectively use the spectrum and time resources, and make the transceiver channel in the Full-duplex operation is realized in the same frequency band, which provides extremely high transceiver isolation for the system. It is a new type of duplexer that integrates the antenna inside the duplexer, as shown in Figure 4. The transmitting and receiving antennas are integrated in the duplexer in parallel, and the polarization forms of the two antennas are guaranteed to be orthogonal. For example, the transmitting antenna adopts horizontal polarization and the receiving antenna adopts vertical antenna. Here, it is only necessary to ensure that the polarizations are orthogonal, or the transmitting antennas may be vertically polarized, and the receiving antennas may be horizontally polarized; or the two antennas may be orthogonally polarized at plus or minus 45 degrees. The transmitting antenna feed port extends to the module interface to form a transmitting port, and the receiving antenna feed port extends to the module interface to form a receiving port. The isolation between the two ports is the transceiver isolation of the duplexer. The more elements that make up the antenna, the greater the gain of the antenna, and the greater the spatial isolation between the two antennas; the greater the distance between the two antennas, the greater the spatial isolation between the antennas. The greater the spatial isolation between the antennas, the greater the transmit-receive isolation between the duplexer's transmit-receive ports.

The radiation unit is designed according to the theory and principles described in the summary of the invention, and after optimization, the structural dimensions are shown in Figure 13 . Among them, a_wg=3.0988mm, b_wg=1.5494mm, L_cp=2.3mm, w_cp=0.7mm, h_cp=0.1mm, L_low=7.4mm, w_low=6.9mm, h_low=0.7mm, L_up=2.7mm, w_up=2.3 mm, h_up=1mm, w_int=0.8mm, h_int=0.5mm.

Using the unit form proposed by the present invention, a planar 4*4 linear array is formed, and its electromagnetic simulation model is shown in FIG. 5 . The array size is 28mm*30mm*3.3mm.

The feed waveguide adopts the standard waveguide flange WR12, and the E-plane T-shaped joint is used to form a power divider. Based on this power divider, the feed network is designed, as shown in Figure 6. Its port performance is shown in Figure 7, return loss S11<-22dB.

The designed array meets the expected requirements, its port return loss is shown in Figure 8, and S11<-10dB in the 71-76GHz frequency band; its gain pattern is shown in Figure 9, the gain is 22dBi, and the first sidelobe level is - 14dBc.

Using the 4*4 array, a duplexer is constructed according to the block diagram in Figure 4. The structural diagram of the duplexer is shown in Figure 10, and the size of the duplexer is 63mm*30mm*4mm. The transceiver isolation is simulated. In the working frequency range of 71-76GHz, the transceiver isolation is greater than 90dB (S21<-90dB), as shown in Figure 11.

A brief example of duplexer and complete machine assembly is shown in Figure 12. The whole machine is composed of shell, transceiver channel, duplexer and radome. The transceiver channels work in the same frequency band, and there is no need to reserve frequency or time guard intervals. The waveguide interface of the transceiver channel circuit and the duplexer are connected through a standard flange, and the two are stacked and installed in the casing of the whole machine. The duplexer integrates the functions of transceiver combination, transceiver isolation, and antenna, which simplifies the composition relationship of the whole machine. The radome is directly used as the upper cover, and it is installed in a sealed manner with the whole machine shell to reduce the weight of the whole machine and form a highly integrated front-end system.

Claims (5)

1. A kind of E-band miniaturization planar antenna, comprises four little radiating elements and a big radiating element, it is characterized in that: described big radiating element is a rectangular element, by the coupling slot in the middle of the rectangular element and be positioned at the rectangular element The feeding waveguide on the side is connected; four identical small radiating units are all rectangular, connected on the upper side of the large radiating unit, forming a 2*2 equidistant rectangular array. 2. The E-band miniaturized panel antenna according to claim 1, characterized in that: the center of the four sides of the large radiation element each has a horizontal cross-section that is a rectangular perturbation slot, and the perturbation slot runs through the large radiation element upper and lower surfaces. 3. E-band miniaturization planar antenna according to claim 1, is characterized in that: the long side length of described small radiating element is the half-wavelength of operating frequency point, and the short side length is no more than half-wavelength of operating frequency point; The period between each small radiating unit does not exceed the wavelength of the working frequency point; the thickness of the small radiating unit does not exceed 1 mm; the long side length of the large radiating unit is one working wavelength, and the width does not exceed half the wavelength of the working frequency point; the large radiating unit The thickness of the perturbation gap does not exceed 1mm; the width and depth of the perturbation gap do not exceed 1mm. 4. The E-band miniaturized panel antenna according to claim 1, characterized in that: the coupling slot between the feed waveguide and the large radiation element is a rectangular slot; the length of the coupling slot is half of the operating frequency point wavelength , the width of the coupling gap does not exceed a quarter of the wavelength of the operating frequency point. 5. a simultaneous co-frequency duplexer utilizing the described E-band miniaturized planar antenna of claim 1 to form, is characterized in that: two E-band miniaturized planar antennas are used as transmitting antenna and receiving antenna, integrated in parallel Inside the simultaneous same-frequency duplexer, the polarization forms of the transmitting antenna and the receiving antenna are orthogonal, the feed port of the transmitting antenna extends to the interface of the simultaneous same-frequency duplexer to form a transmitting port, and the feed port of the receiving antenna extends to the simultaneous same-frequency duplexer The receiving port is formed at the interface of the duplexer.