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A novel compact coplanar stripline (CPS)-fed antenna for ultra-wideband (UWB) application is investigated. The proposed antenna consists of a staircase-shaped radiator together with a shorted strip. The prototype is designed on a substrate of dielectric constant 4.4, with an overall size of 25 × 7 × 1.6 mm 3 . The antenna offers a 2:1 voltage standing wave ratio (VSWR) bandwidth from 3.1 to 11.4 GHz, with an average gain of 3 dBi and average radiation efficiency of 75% throughout the band. The measured group delay and transmission characteristics show that the proposed antenna is a good candidate for UWB communication systems.Introduction: Ultra-wideband (UWB) technology has been expanding rapidly as a promising technology for many applications such as ground penetrating radars, location tracking and data communication, since the FCC specified 3.1-10.6 GHz as the frequency band for UWB radio systems. UWB is conventionally recognised as impulse radio, which transmits data in short pulses and is devoted mainly to short-range applications due to the limitations of the power spectral density of −41.3 dBm/MHz within the UWB band [1]. One of the biggest advantages of UWB is its immunity against fading effects. The modern era of communication is in need of small and miniaturised UWB antennas for many applications such as wireless universal serial bus, wireless body area networks etc. Considerable research efforts have been made towards the design of miniaturised UWB antennas [2][3][4]. A compact UWB antenna which consists of a microstrip-fed monopole, printed on a 13 × 22.5 mm 2 substrate, with a truncated ground plane loaded with a dielectric resonator was discussed in [5]. A small coplanar waveguide-fed UWB antenna was presented in [6] with a fairly compact size of 19 × 16 mm 2 . The compactness of the antenna was achieved by exploiting a quasi-self-complementary structure together with a tapered radiating slot.In this Letter, we propose a compact coplanar stripline-fed UWB antenna with a staircase-shaped radiating element and a shorted strip. A 40% reduction is achieved in the overall area, compared with the one discussed in [5] and 42% compared with [6]. Simulated and measured studies show that the proposed antenna offers good radiation characteristics in the entire UWB band. The three-dimensional (3D) electromagnetic simulator software of CST Microwave Studio is used for simulating the antenna.

A fully printable, passive, compact, and polarization‐independent chipless radio frequency identification (RFID) tag is proposed. A symmetric cross loop resonator is the basic scattering element. The prototype of the tag is fabricated on RT Duroid 5880 substrate with εr = 2.2, tan δ = 0.0008, h = 1 mm. Data is coded in the frequency domain with multiple resonators. A 20‐bit tag of dimensions 4 × 4 cm2 is demonstrated. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:944–947, 2016

Fully printable polarization independent frequency domain chipless radiofrequency identification tag using the harmonic separation capability of Stepped Impedance Resonator is proposed. The data are encoded either using the magnitude or group delay of the backscattered signal. The data encoding capacity of the tag is enhanced using Frequency Shift Coding technique. Radiofrequency identification (RFID) is a wireless data capturing technique which uses RF waves for extracting the encoded data from remotely placed objects whose applications include pallet identification, road toll system, item tracking, fare collection system, and so forth. Chipless tags which require neither integrated circuit nor remote/self-empowerment are the current trend in the field of RFID. These printable chipless tags can also be used as a good alternative to the existing barcode technology [1]. Many fully passive printable frequency domain chipless RFID tags based on multiple scatterers are discussed in [2][3][4][5][6][7][8][9]. These scatterers act like radar targets and they will generate a unique spectral ID to encode data. Data encoding capacity, polarization, reradiation pattern, higher harmonic frequency separation/suppression, and readable range are the characteristics for the selection of the scatterers. The first RFID tag using multiple scatterrers was reported by Jalaly and Robertson [6] based on RF barcodes which are constructed with arrays of metallic microstrip dipoles on a dielectric substrate with ground plane. But many narrow bands were straddled with increase in bit encoding capacity. Polarization insensitive tag using nested circular rings is reported in [7] but the usable bandwidth is limited due to higher harmonic frequency. Independent control over fundamental and first harmonic frequency of k/4 (where k is the guided wave length) and k/2 stepped impedance resonator (SIR) structure is exploited to achieve high data encoding capacity with multiple bits per resonator [8]. But the tag is sensitive to the polarization of incident wave. A compact printable dual polarized chipless RFID system is presented in [9]. Here, two sets of slot resonators are placed with orthogonal polarizations to double the bit encoding capacity within the same frequency band. The readable range of the tag reported is only 5 cm and it suggests a less reliable technique of symmetric excitation for harmonic suppression. Two types of SIR-based tags are proposed in this article. Tag-I is polarization insensitive to the incoming waves and Tag-II is with enhanced data encoding capacity. Independent control over harmonic frequencies of SIRs enables wide band utilization to encode more data. Structural information in the tag can be decoded using magnitude or group delay of the backscattered signal. With Frequency Shift Coding (FSC), the surface coding density of Tag-I is 0.61 bits/cm 2 and of Tag-II is 1.22 bits/cm 2 . The proposed design provides a readable range of 40 cm without any additional detection algorithm. TAG DESIGN USING SIRSIRs ar...

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