Planar circularly polarized microstrip antenna with a single feed

It is well-known that the circular polarization (CP) bandwidth of a microstrip antenna is greatly related to its impedance characteristic. Several broadband antenna structures have been proposed and studied, such as using a thick substrate with low permittivity and a multi-resonator structure. Another method to enhance the impedance bandwidth is using slot antennas instead of the microstrip antennas. In this paper, a new CP design developed from the ring slot antenna is proposed. The antenna structure composed of a wide slot and a parasitic patch is with wideband characteristics. By adjusting the distance between the wide respectively, which are obviously higher than that of a same-size microstrip antenna. Also, the CP designs of wide slot antennas have been investigated to further improve the CP bandwidth. By protruding a T-shaped [3] or an L-shaped strip [4] from the ground plane, the CP bandwidth of the wide slot antenna can reach to 18 %. However, the available designs for the slot antenna with more than 20 % CP bandwidth are relatively few in the open articles. In this paper, a new CP design developed from the ring slot antenna is proposed. The antenna structure composed of a wide slot and a parasitic patch is with wideband characteristics. By adjusting the distance between the wide slot and parasitic patch, the CP bandwidth can be varied between 5 and 45%. Details of the proposed designs and the obtained results are shown and discussed.

A novel circularly polarised (CP), single-fed microstrip antenna is presented. The antenna consists of stacked structure of a rectangular patch over a rectangular ring. The proposed design has a reduced antenna size as compared to the conventional CP microstrip antenna at a given operating frequency. The impedance and axial ratio bandwidths are large and CP radiation quality is excellent over the entire upper hemisphere. These antennas feature more than 9dBi gain. The proposed antenna is suitable for global positioning system (GPS) applications.

This paper presents a single-feed circularly polarized (CP) microstrip antenna achieved by defected ground structure. With the proposed DGS, a new resonant mode is added, which is orthogonal to the original resonant mode. These two modes will have the same magnitude and the 90° time-phase difference by adjusting the DGS dimensions, which contributes to achieve the CP radiation. Both the simulated and measured 10-dB impedance bandwidth of the CP microstrip antenna are 30 MHz, while the 3-dB axial-ratio bandwidth is 6 MHz. The CP gain across the 3-dB AR band ranges from 4.6 to 5.0 dBic.

This paper proposes new design of square microstrip antenna with dual feed line for improving bandwidth and axial ratio at work frequency of 2400 MHz. To obtained circular polarization with axial ratio ≤ 3 dB and enhanced bandwidth of antenna, dual feed line is used to improve performance of conventional microstrip antenna. After the simulation process, dual feed line succeed to improved bandwidth of microstrip antenna 131.9 % compared with microstrip antenna with single feed and provide circular polarization with axial ratio 2.44 dB at working frequency of 2400 MHz. compared to the microstrip antenna with a single feed. This research is very usefull for Wi-Fi application in order to improve the level quality of receiver signal.

Design of a coplanar waveguide (CPW) feed square microstrip antenna with circular polarisation (CP) radiation is described. This CP design is achieved by using an asymmetric inductively coupling slot in the ground plane of the CPW feed line. Results show that the proposed antenna can have a CP bandwidth of 2.4%, whereas a simple inclined coupling slot case has 1.6% CP bandwidth at a fixed square patch size. Typical experimental results are presented and discussed.

This paper presents a new design of a probe-fed circularly polarized equilateral-triangular-ring (ETR) microstrip antenna. In this design, the ETR patch is modified to have a truncated tip and a Y-shaped conducting strip of equal arm lengths centered in the patch center and connected to the three tips of the patch. With the proper size of the truncated tip, the splitting of the fundamental resonant mode of the modified ETR microstrip antenna into two near-degenerate orthogonal modes for circular polarization (CP) radiation can be achieved by using a single probe feed located in the Y-shaped conducting strip. In addition to the good CP radiation obtained, the proposed modified ETR microstrip antenna can perform CP radiation with a reduced antenna size as compared to a regular circularly polarized equilateral-triangular microstrip antenna at a fixed operating frequency. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 123–126, 1999.

A new technique to design single-feed circularly polarized (CP) microstrip antenna is proposed. The CP radiation is obtained by adjusting the dimension of the etched fractal defected ground structure (FDGS) in the ground plane. Parameter studies of the FDGS are given to illustrate the way to achieve CP radiation. The CP microstrip antennas with the second and third iterative FDGS are fabricated and measured. The measured 10-dB return-loss bandwidth of the CP microstrip antenna is about 30 MHz (1.558 to 1.588 GHz), while its 3-dB axial-ratio bandwidth is 6 MHz (1.572 to 1.578 GHz). The gain across the CP band is between 1.7 and 2.2 dBic.

A simple design of a probe-feed microstrip antenna with circular polarization (CP) radiation is presented. By embedding dual slits in a square microstrip and adjusting the sizes of the slits, an H-shaped microstrip antenna with two near-degenerate orthogonal modes for CP radiation can be achieved. This design provides a wide CP bandwidth and relaxed fabrication tolerances. Details of the antenna design are described, and theoretical and experimental results of the CP performance are presented.

A common property of microstrip antennas is that the antenna element launches surface wave modes in addition to the radiated fields. Suppression or reduction of surface waves improves antenna efficiency and reduces side lobe levels. EBG materials, also known as photonic crystals, can offer a solution to the surface wave problem. A novel circularly polarized (CP), single-fed microstrip antenna on an electromagnetic bandgap (EBG) substrate is presented. The antenna consists of a stacked structure of almost square patches and an EBG substrate for the lower patch. The proposed design has a reduced antenna size as compared to the conventional CP microstrip antenna at a given operating frequency and is of light weight. The impedance and axial ratio bandwidths are large and CP radiation quality is excellent over the entire upper hemisphere. The antenna features about 11 dBi gain. The proposed antenna is suitable for Global Positioning System (GPS) applications.

Novel designs of single-feed equilateral-triangular microstrip antennas for circular polarization (CP) are proposed and studied experimentally. It is demonstrated that by embedding a narrow slot or a cross slot of unequal slot lengths in the triangular patch, circularly polarized radiation of microstrip antennas can easily be achieved using a single probe feed. Furthermore, results show that for the design with a cross slot, the proposed antenna can perform CP radiation with a reduced antenna size at a given frequency (denoted as compact CP operation here); that is, the required antenna size is smaller for the proposed antenna for performing CP radiation as compared to a conventional circularly polarized triangular microstrip antenna at a fixed operating frequency. Details of the proposed CP designs are described, and typical experimental results are presented and discussed.

Several microstrip antenna (MSA) configurations are available to generate the circular polarization (CP), which can be obtained by either single feed or dual feed. Square or circular MSA fed at two orthogonal points with equal amplitude and 90/spl deg/ phase difference yields wider axial ratio bandwidth than the single feed MSA, but the VSWR bandwidth is small. In this paper, several stacked MSA configurations using either square or circular patches have been proposed to increase both the axial ratio and VSWR bandwidths with higher directivity. Only one patch at the bottom layer is fed at two orthogonal points with equal amplitude and 90/spl deg/ phase difference, and the other parasitic square or circular patches are stacked to yield broadband CP. These antennas have been analyzed using the IE3D software based on the method of moments.

This paper presents a method of wideband circular polarization (CP) generation using a stacked patch-ring microstrip antenna with a single probe feed. An enhanced axial ratio (AR) bandwidth is obtained when a combination of a square ring and a square patch with negative perturbations is used as parasitic and driven elements, respectively. The axial ratio bandwidth obtained is significantly larger compared to the case when square rings are used as parasitic and driven rings with a single feed. A simulated impedance bandwidth (Sn< −10dB) of 16%, 3dB AR bandwidth of 8%and a peak gain of 8.65 dBic are obtained from this antenna.

A novel design of slotted equilateral-triangular microstrip antenna and its array is proposed to achieve wider circular polarization bandwidth. The proposed structure consists of nearly cross-slot antenna to generate circular polarization then two equilateral-triangular microstrip elements are composed sequentially to achieve wider axial ratio bandwidth.

A broad beamwidth stacked patch antenna with wide circularly polarised (CP) bandwidth is presented. The proposed antenna consists of a stacked structure with a rectangular shell under its ground structure to obtain CP characteristics and wide beamwidth. The radiation quality is excellent over the entire upper hemisphere. The 3 dB beamwidth of the proposed antenna on 2.4 GHz is larger than 140°. Moreover, the CP bandwidth, determined from the 3 dB axial ratio, is found to be about 240 MHz. CP bandwidth of 10.2% and the impedance bandwidth of 52.8% centred on 2.4 GHz are obtained. The proposed antenna is a good candidate for wide angle scanning phased arrays.

This paper presents the design of a novel reflective linear-to-circular polarization conversion metasurface (PCM) and its application to a wideband high-gain circularly polarized (CP) antenna. The proposed PCM efficiently converts incident linearly polarized (LP) waves into CP waves within an ultra-wideband range of 11.8-28.6 GHz, thereby laying a solid foundation for the design of the wideband CP antenna. By adding an LP microstrip antenna as the feed source above the PCM, the metasurface leverages its polarization conversion capability to reflect CP waves, simultaneously enhancing the antenna gain, and thus yields a wideband high-gain CP antenna. The designed CP antenna exhibits an impedance bandwidth and a 3-dB axial ratio (AR) bandwidth both spanning from 13.2 to 18.6 GHz, corresponding to a relative bandwidth of 34%. Notably, the 3-dB AR bandwidth perfectly matches the impedance bandwidth. Meanwhile, the antenna maintains a stable high gain exceeding 11 dBi across the entire operating bandwidth. Excellent agreement is achieved between the measured and simulated results, confirming that the proposed antenna simultaneously achieves a wide CP operating bandwidth, full-band 3-dB AR coverage, and high gain. Such characteristics make it highly valuable for potential applications requiring both wideband CP operation and high gain, such as microwave communications, precision radar, and satellite navigation systems.