Compact Low-Profile Differential Filtering Microstrip Patch Antenna With High Selectivity and Deep Rejection Using Single-Layer Substrate

Abstract

A compact low-profile differential filtering microstrip patch antenna with high selectivity and deep rejection using single-layer substrate is proposed. The presented antenna mainly consists of the quasi-H-shaped patch (QHSP) and the meandering quasi-T-shaped resonator (QTSR) which is composed of two open-end meandering arms in opposite direction and an inset coupling structure. To the best of our knowledge, a novel differential feeding structure is adopted for the first time that a pair of differential inset coupling feeding structures are placed in opposite direction to drive the QHSP with insetting-capacitivecoupling, simultaneously. Its equivalent lumped circuit is further analyzed to study the characteristics. In the point of views of filter and antenna design, the meandering QTSR not only acts as the first stage of resonator, but also a feed structure, and the QHSP can be treated as the last order of resonator as well as the radiator. A prototype of the proposed antenna is designed, analyzed, simulated and measured. Two controllable radiation nulls (RNs) locate at the both sides of the passband, a sharp skirt selectivity with the sideband roll-off rates of 667/182 dB/GHz and out-of-band suppressions of -40.1/-39 dB in lower and upper stopbands are achieved, respectively. The measured flat realized gain can be obtained in the passband with the average gain more than 6 dBi and the low cross-polarization level can be achieved. The dimension of the proposed antenna is only 0.361λ 0 ×0.426λ 0 ×0.013λ 0 . Good agreement between the simulated and measured results is obtained, which verifies the proposed antenna with the differential feeding structure has excellent performance only using single layer low profile substrate. The proposed antenna is a good candidate for WLAN and power harvest application.

Compact 5G Vivaldi Tapered Slot Filtering Antenna with Enhanced Bandwidth

“…On the other hand, using filters is more efficient in controlling the required narrow band with high selectivity and out-of-band rejection levels. Patch [6][7][8][9][10][11], and monopole [2,[12][13][14][15][16] antennas are the most commonly used in the literature for filtering antennas (filtennas design. However, loop [17], dipole [18], quasi-Yagi [19], slot line [20], Vivaldi [21] and Metasurface (MS) [22] antennas are not widely employed.…”

“…More practically, compact wearable filtennas with circular polarization suitable for offbody wireless communications are designed in [7,8] by integrating a square patch antenna with an open-loop resonator (OLR) BPF using coupled stripline and pins. High selectivity in filtenna can be achieved using a differential feeding structure [9,10]. In [9], three patches and a line resonator are used to enhance the performance and increase the harmonic suppression level, respectively.…”

“…In [9], three patches and a line resonator are used to enhance the performance and increase the harmonic suppression level, respectively. However in [10], this structure is applied to mitigate the cross-polarization level and improve the selectivity and out-of-band suppressing levels (−40.1/−39 dB) by integrating a quasi-H-shaped patch (QHSP) and a meandering quasi-T-shaped resonator (QTSR). A 30% size reduction with wide-band harmonic rejection is obtained in [11] by integrating a rectangular stub to the feedline of the ultra-thin fractal patch antenna.…”

Bandwidth improvement of differential‐fed patch antenna with out‐of‐band rejection using SISL technology

“…In wireless communication systems, antennas with filtering performance without any extra filtering circuit attract more interest in reducing loss and miniaturizing the system. Different techniques have been reported for this purpose, such as placing a pair of inset coupling structures in the opposite direction of the quasi-Hshaped patch, 7 introducing a pair of parasitic patches along the nonradiative edges of the center patch, 8 attaching the coplanar coupling structures and a set of shorting pins to the driven rectangular patch. 9 However, the fabrication cost 7,8 increases due to the use of expensive dielectric material, and the method increases the volume of the design.…”

“…Different techniques have been reported for this purpose, such as placing a pair of inset coupling structures in the opposite direction of the quasi-Hshaped patch, 7 introducing a pair of parasitic patches along the nonradiative edges of the center patch, 8 attaching the coplanar coupling structures and a set of shorting pins to the driven rectangular patch. 9 However, the fabrication cost 7,8 increases due to the use of expensive dielectric material, and the method increases the volume of the design. Therefore, it is an ongoing challenge to design low-cost patch antennas with both wide bandwidth, low cross-polarization, high gain, and filtering functions within a limited volume.…”