Dual polarised patch antenna

To verify the radiation performance of designed antenna itself, a test package including two patch antennas is also design and its scattering parameters were measured. Using a large height of dielectric materials, 1. Besides, the dielectric constants are reduced to reflect variances of material properties in the higher frequency region.

Measured results of the test package show a good performance at the operating frequency, indicating that the fabricated antenna package will perform well, either. Differential feeding for dual-polarized patch antennas design can help to decrease cross-polarization and increase port-to-port isolation [ 10 , 11 ].

However, the antennas have narrow impedance bandwidth. Recently, a dual-polarized patch antenna fed by a wide balun can realize wide working band, low cross-polarization, and high isolation performances [ 12 ]. In this paper, a dual-polarized patch antenna fed by a hybrid ring structure is proposed. The proposed antenna adopts shape strips coupled feeding structure [ 13 ] to achieve wide working band.

And a novel hybrid ring is applied as a feeding network. The hybrid ring feeding network has a broadband high isolation characteristic. The hybrid ring feeding structure consists of eight lines and two orthogonal-offset differential feeding lines for two polarizations. And the hybrid ring feeding structure can realize twice the power cancellation to the other port when one port is excited. Thus, the ports isolation within a wide bandwidth is highly enhanced. Moreover, due to the differential feeding and fully symmetric structure, low cross-polarization level can be obtained.

The proposed dual-polarized patch antenna has good performances of broad impedance bandwidth, high isolation, and low cross-polarization level. The hybrid ring feeding network is shown in Figure 1. It is a ring which is composed of eight lines and two orthogonal-offset differential feeding lines, where is the guided wavelength of the center frequency.

The two differential feeding lines are printed on two different substrates to avoid intersection. The quarter-wavelength impedance transformer line and differential feeding line of Port 2 and the quarter-wavelength impedance transformer of Port 1 in green are printed on the top of the upper substrate, and the differential feeding lines of Port 1 and eight lines of the ring in yellow are printed on the bottom face of the lower substrate.

The feeding lines printed on different substrates connect to each other via three probes. The ground plane is arranged between the two substrates. The differential feeding line of Port 1 consists of a power divider and a half-wavelength delay line.

And a quarter-wavelength impedance transformer is used to achieve good impedance match. An equivalent structure of the hybrid ring feeding network is illustrated in Figure 2.

The working principle of the hybrid feeding network is analytically and numerically analyzed as follows: the impedances of Ports 3—6 and the half-wavelength delay lines are.

The characteristic impedance of each microstrip line of the hybrid ring is , and the impedance of each impedance transformer is. The equivalent circuit can be simplified as in Figure 3. Then, the output impedance of point B is ; after the impedance transformer, the impedance of Port 1 becomes.

The impedance of Port 2 is also. When is equal to and the center frequency is 2. It can be seen that a very deep transmission zero is located at the center frequency.

The deep transmission zero is produced by twice the power cancellation. When Port 1 is excited, signals will firstly cancel at point B and point b. Additionally, a half-wavelength delay line is employed between point A and point a, and the signals will cancel again. Moreover, the signals from Port 1 are equally split to Ports 3—6, wherein Ports 3 and 6 are with in-phase signals, as well as Ports 4 and 5.

However, the two pairs of ports are with out-of-phase signals, while, with Port 2 excitation, the signals from Port 2 will also be equally split to Ports 3—6. Then, Ports 3 and 4 are with in-phase signals, as well as Ports 5 and 6. Ports 3 and 4 and Ports 5 and 6 are then two pairs of out-of-phase ports. Figure 5 shows the simulated -parameters of the hybrid feeding network with different half-wavelength delay lines of Port 1 and Port 2. It is clearly seen that the isolated bandwidth of the hybrid feeding network can be tuned by changing the operating frequencies of half-wavelength delay lines of Port 1 and Port 2.

When or is the wavelengths of half-wavelength delay lines of Port 1; is the one of Port 2 , the transmission zero produced by the half-wavelength delay line of Port 2 will shift to the higher frequency or lower frequency, and the zero produced by the half-wavelength delay line of Port 1 is unchanged.

When , , the zero produced by the half-wavelength delay line of Port 1 will also shift. Based on the above analysis, we can know that the hybrid feeding network can realize good impedance matching and high ports isolation in a wide operating band. The geometry of the proposed dual-polarized patch antenna is shown in Figure 6.

It consists of five substrates: the upper horizontal substrate 1 , the middle vertical substrates 2 and 3 , and the bottom horizontal substrates 4 and 5. The radiating circular patch is printed on one of the horizontal substrates 1. The four shaped strips are printed on the vertical substrates 2 and 3 and soldered to Ports 3—6 of the hybrid ring feeding network via four probes.

The quarter-wavelength impedance transformer and differential feeding line of Port 2 and the quarter-wavelength impedance transformer of Port 1 are printed on the top layer of the horizontal substrate 4 , and the hybrid ring with the differential feeding line of Port 1 is printed on the bottom layer of the horizontal substrate 5.

The ground is between the two horizontal substrates 4 and 5. This air layer is designed to widen the working band. All the five substrates are with dielectric constant , loss tangent , and a thickness of 0. The center frequency of the proposed antenna is 2. The ports impedances of the hybrid ring feeding network are Signals from Port 1 transport along quarter-wavelength impedance transformer, and then they split into two equal and out-of-phase components by the differential feeding lines of Port 1.

The degree phase shift is caused by a half-wavelength delay line. Very good isolation values are obtained by a suitable combination of these measures for example notches and cut-off corners or the like. The described microstrip patch antenna 43 has a very narrow bandwidth. This bandwidth can be increased by the use of additional patches, which are placed on the already existing patches, at a distance from them.

The isolation can be improved further by a suitable combination of the patch modifications. For example, the lower patch has notches and the upper patch has lugs. The polarization is governed by the connections and feed of the lower patch. The isolation in an array comprising a plurality of individual elements arranged alongside one another can be improved by the patches in the individual elements having different modifications.

A dual-polarized microstrip patch antenna having one or more individual elements with each of said one or more individual elements having at least one rectangular patch arranged on the upper face of a printed circuit board having a feed network on said upper face and having metallization over the entire surface of the lower face, wherein said feed network permits feed to take place only at two corners of the patch, and wherein said at least one patch has modifications that improve the isolation between the polarizations of said one or more individual elements, in comparison to an unmodified patch.

The antenna of claim 1 , wherein said modifications are arranged at the edges of said patch. The antenna of claim 2 , wherein said modifications comprise two notches on opposite edges of said patch. The antenna of claim 3 , wherein said notches are rectangular and have a width of up to about 0. The antenna of claim 2 , wherein said modifications comprise two lugs on opposite edges of said patch. The antenna of claim 5 , wherein said lugs are rectangular and have a width of up to about 0.

The antenna of claim 2 , wherein said modifications comprise cut-off corners at the corners of said patch. The antenna of claim 1 , wherein said modifications are arranged in the center of said patch.

The antenna of claim 9 , wherein said modifications comprise a slot which runs parallel to the edges of said patch. The antenna of claim 10 , wherein said slot is rectangular and has a length of up to about 0. The antenna of claim 1 , wherein a plurality of different modifications are combined with one another for said at least one patch.

The antenna of claim 1 , wherein said patch is arranged with the edges parallel to the x axis and y axis of the antenna. The antenna of claim 1 , wherein a plurality of patches are arranged at a distance one above the other within the individual elements to increase the bandwidth.

The antenna of in claim 15 , wherein said plurality of patches of an individual element have at least one of different modifications and a different orientation of the edges with respect to the x axis and y axis of the antenna.

The antenna of claim 15 , wherein said upper patches are mounted on the printed circuit board by means of spacers. The antenna of claim 1 , wherein a plurality of individual elements are arranged alongside one another in an array. The antenna of claim 18 , wherein said patches of said individual elements in an array have at least one of different modifications and are a different orientation of the edges with respect to the x axis or y axis of the antenna. The antenna of claim 1 , wherein said printed circuit board is mounted on a metal sheet, with the patches, by means of spacers, and the metal sheet can be inserted into a shroud which is open on one side.

The antenna of claim 1 , wherein said patch is square. USB2 en. EPA1 en. CNA en. AUA1 en. WOA1 en. Method and apparatus that isolate polarizations in phased array and dish feed antennas. Mobile wireless communications device including an electrically conductive director element and related methods.

A kind of corner-fed high isolation dual polarized stacked microstrip antenna of modified model. CNB en. JPSA en. USA en. EPA2 en. USA1 en. Dual-polarized radiating element with high isolation between polarization channels. USB1 en. Ultra wide band balanced antipodal tapered slot antenna and array with edge treatment. KRB1 en.