A CPW‐fed two‐arm spiral slot antenna

Abstract

In this article, the S parameters of the prototype were measured using a vector network analyzer (Agilent E5071B).When the port 1 is excited and the port 2 is terminated to a 50-⍀ load, the measured and simulated S parameters of the prototype are shown in Figure 7. The measured impedance bandwidth, defined by Ϫ10 dB return loss, reaches 630 MHz (1860 -2490 MHz), which covers the UMTS band and 2.4-GHz WLAN band. Across the two bands, the isolations of the prototype are larger than 14 and 18 dB respectively. Because of the symmetric configuration, S 22 (S 12 ), which is not given in this article, is consistent with S 11 (S 21 ).When one of the two ports is excited and the other port is terminated to a 50-⍀ load, the radiation patterns of the proposed antenna are measured in an anechoic chamber. Figures 8 and 9 show the patterns of the two monopoles at 2.05 GHz, respectively. The measured patterns at 2.44 GHz, which have not been shown in this article, have similar characteristics with those at 2.05 GHz. One can find that the measured radiation patterns of monopole 1 and 2 cover complementary space regions, so the proposed diversity antenna can provide pattern diversity in a wireless communication system.In this article, the antenna efficiency is approximately calculated by ABSTRACT: A wideband coplanar waveguide (CPW)-fed two-arm spiral slot antenna without a balun circuit is presented in this article.Phase progressions at arm ports are realized through the coplanar waveguide excitations. A detailed characterization of all antenna components and parameters is provided along with guidelines and recom-mendations for broad bandwidth and small reflection. Variations of the impedance matching due to the turn numbers, the ground width separated between two neighboring turns and the slot width are tested and studied. The measured impedance bandwidth of a S 11 Յ 10 dB ranges from 1.63 to 8 GHz and covers most of the commercial wireless communication systems, such as DCS, PCS, IMT-2000, WLAN, Bluetooth, and HIPERLAN. ABSTRACT: The modified Yule-Walker scheme is employed to define arbitrary transmission scattering parameter of a multiple-level bandpass filter in the discrete-time domain. Equal-length microstrips including single-and double-section stubs are used to implement the multiplelevel band-pass filter. Experimental results are presented to illustrate the validity of this design method.

A CPW‐fed wideband spiral slot antenna with circular polarization

“…The comparison of axial ratio (AR) and phase difference (PD) between two orthogonal electrical fields of the proposed spiral slot antenna are shown and discussed. The antenna can provide broad impedance bandwidth and axial-ratio bandwidth compared to the antenna in [4]. Useful applications in commercial communication systems and in satellite navigation systems can be found.…”

“…This article presents further investigation of the CPW-fed two-arm spiral slot antenna, discussed in [4]. Techniques for improving the circular polarization bandwidth are proposed by embedding an arc slot beside the spiral slots, varying the turn number of the spiral slots, and changing the separation between the arc slot and the spiral slots.…”

“…The antenna is particularly popular due to well-established broadband feeding schemes for various radiation modes. In [4], a wideband CPW-fed two-arm spiral slot antenna without a balun circuit is presented. The positive and negative signals split from the CPW feeding line are injected into the two-arm spiral slot antenna.…”

“…Several spiral slot antennas are reported to achieve improved performances, particularly for feeding structure [1][2][3][4] and size miniaturization [5][6]. The antenna is particularly popular due to well-established broadband feeding schemes for various radiation modes.…”

A Spiral Antenna With Integrated Parallel-Plane Feeding Structure

“…This method achieves a completely planar spiral antenna at the cost of limited band width [4]. The coplanar waveguide (CPW)-fed slot antenna has received considerable attention [5][6][7]. Despite the advantages of completely planar structure, the CP (circularly polarization) bandwidth is also limited.…”