A Circularly Polarized Antenna Array With a Convenient Bandwidth/Size Ratio Based on Non-Identical Disc Elements

Abstract

Abstract-This paper presents the design and development of a circularly polarized microstrip antenna array for C-band application. The proposed antenna has a convenient trade-off between bandwidth and dimension. The array design is based on the sequential phase arrangement (SPA) of 2 × 2 non-identical disc-based patch elements, operating in modal degeneration. Exploiting the properties of the SPA, capable of forcing CP even when operating on linear polarized elements, each disc is independently detuned to operate on non-perfectly overlapping bands. When properly fed by a sequential phase network (SPN), the set of four discs seamlessly covers the wide cumulative bandwidth which is the combination of the four sub-channels. To verify the design, a single-layer via-less array was fabricated in a compact printed square board of side 40 mm, meaning a surface of 0.64λ 2 0 at the center frequency of 6.0 GHz, assembling the elements with a compact space-filling SPN. Measurements show a wide 10 dB return loss bandwidth of 28.5%, a 3 dB axial ratio (AR) bandwidth exceeding 1 GHz, and a realized gain ranging from 4.1 dB to 7.25 dB inside the AR bandwidth. The global bandwidth of the proposed array, almost coincident with the AR bandwidth, is 17.0%.

A Compact Two-Level Sequentially Rotated Circularly Polarized Antenna Array forC-Band Applications

“…To cope with the strongly resonant behavior of the antenna impedance, depicted in Figure 3(a), the solution introduced in [21,24] and shown in Figure 4(c) is applied here. The main improvement regards the implementation of the four MNs as tapered lines instead of QWTs.…”

A Circularly Polarized Antenna for Dual Band Operation at 2.45 GHZ and 5.10 GHZ

“…This kind of design was introduced in [17][18][19], hence it is only briefly summarized in this section. The disc radius is R, while the ellipse axes are A and B.…”

“…Because of the quasi-symmetrical perturbation inducted by the ellipse, the fundamental mode is divided in two orthogonal components, labeled as TM 1x and TM 1y . Their respective resonant frequencies f 1 and f 2 still depends on R, but are also inversely proportional to A and B [19]. When both modes are excited with the same magnitude and in phase quadrature, the resulting far-field is in a perfect CP condition [20].…”

16‐Element circular polarised antenna array based on sequential arrangement of non‐identical disc patches

“…Element design: The proposed antenna is based on a disc-based patch already employed for the sequentially rotated array [1,2]. Hence it is only briefly summarised for the sake of completeness.…”