Quarter-wavelength Transformer Research Articles

Semi-Passive RFID Electronic Devices With On-Chip Sensor Fusion Capabilities for Motion Capture and Biomechanical Analysis

This paper presents the development and testing of a novel electronic device for Wireless Motion Capture (W-MoCap), a technology that allows the reconstruction of movements of objects and body parts with many potential applications in various contexts. The device integrates UHF RFID technology with sensors for low-power backscattering communication. It consists of a Battery Assisted Passive UHF RFID chip, an Inertial Measurement Unit, an ultra-low power microcontroller, and a custom-designed edge-fed body-tolerant antenna operating at 866 MHz. The proper matching between the RFID chip and antenna is ensured through a well-designed L-match unbalanced network, and the separation of RF and DC signals is achieved with a meandered microstrip quarter-wavelength transformer, choke inductor, and decoupling capacitor. The designed and realized RFID W-MoCap Sensor-Tag has been thoroughly evaluated in terms of current consumption, front-end sensitivity, and sensing accuracy. Finally, five prototypes have been applied to specific segments of a human subject and successfully tested in a practical scenario for real time reconstruction of human movements.

High-Sensitivity Slot-Loaded Microstrip Patch Antenna for Sensing Microliter-Volume Liquid Chemicals with High Relative Permittivity and High Loss Tangent.

This paper proposes a microwave sensor based on a high-sensitivity slot-loaded rectangular microstrip patch antenna (MPA) for measuring microliter-volume liquid chemicals with high relative permittivity and high loss tangent. A rectangular single-ring complementary split ring resonator (SR-CSRR) slot with a bottom-edge center split (BCS) was inserted along the upper radiating edge of the patch to enhance the relative permittivity sensitivity of the MPA. The first resonant frequency of the proposed SR-CSRR-BCS slot-loaded MPA showed the highest sensitivity compared to the resonant frequencies of the MPAs with other commonly used slots for varying the relative permittivity of the planar substrate type material under test from 1 to 10 when placed above the patch. After designing the scaled SR-CSRR-BCS slot-loaded MPA with the unloaded first resonant frequency at 2.5 GHz, a hollow acrylic cylindrical liquid container with an inner volume of approximately 18.6 μL was placed at the top-edge center of the SR-CSRR-BCS slot to achieve maximum sensitivity. A quarter-wavelength transformer was applied between the patch and the feed line of the MPA to improve the impedance mismatch that occurs when liquid chemicals with a high loss tangent are placed in the container. Water, methanol, and ethanol were carefully selected for test liquids to cover a broad range of relative permittivity and high loss tangents. The proposed SR-CSRR-BCS slot-loaded MPA was designed and fabricated on a 0.76 mm-thick RF-35 substrate, and a reference RS-loaded MPA was designed and fabricated for comparison. The shift in the first resonant frequency of the input reflection coefficient characteristic was used for the sensitivity comparison, and the container was filled with 15 μL of the liquids at 25 °C. The measured sensitivity (%) of the proposed SR-CSRR-BCS slot-loaded MPA for water was 0.45%, which was higher than other antenna-based microwave sensors in the literature.

Design of an E-sectoral horn based on PRGW technology for 5G applications

AbstractE-plane sectoral horn antenna based on printed ridge gap waveguide (PRGW) technology is designed for 5G applications. It is implemented on the top plate of the PRGW structure to avoid the losses and dispersion associated with conventional feeding mechanisms. The quasi-transverse electromagneticPRGW-based antenna is excited through a planar microstrip transition. First, the single horn antenna element is introduced with the microstrip feeding section. It shows an impedance bandwidth of fractional bandwidth 26% from 45.7 to 55.4 GHz with the realized gain of 12.7 dBi and radiation efficiency of 90%. In order to maximize the realized gain, a four-element linear horn array is introduced. The same impedance bandwidth is maintained with the array having a gain of 18.6 dBi from 45.7 to 55.4 GHz. The overall antenna array performance in the entire operating frequency range is stable with a radiation efficiency around 85%. Three matching sections are implemented to achieve better impedance matching. One is used to match the horn with the feeding aperture via the PRGW line. Another section is designed to match microstrip transition with PRGW ridge. Finally, two-stage quarter wavelength transformers are required to match the power divider with the array feeding network. A prototype of single-element horn antenna was fabricated to verify the concept of the design. Simulated and measured results show that the proposed antenna can operate in the frequency band of 45–55 GHz with good agreement of radiation performance. Moreover, the proposed designs are implemented and simulated using two microwave simulation tools (CST and HFSS) to verify the radiation performance, which exhibits good agreement. The design of an E-sectoral horn antenna and its array with high gain based on PRGW is demonstrated for the first time which is considered a novel issue. It can be integrated with other passive and active elements in communication systems. Thus, it can be a valuable component in 5G communication due to its high gain, compact size and ultra-wide band.

Design and Realization of a Broadband Multi-Beam 1×2 Array Antenna Based on 2×2 Butler Matrix for 2.45 GHz RFID Reader Applications

This paper presents design and analysis of a beam switchable [Formula: see text] array patch antenna fed by a [Formula: see text] Butler matrix based hybrid coupler for 2.45[Formula: see text]GHz radio frequency identification (RFID) reader applications in the ISM band. The proposed beam switchable array antenna arrangement consists of two identical patch elements, a pleated quarter-wavelength impedance transformer (PQWIT), and a hybrid coupler. The concept of PQWIT has been utilized to reduce the overall implementation area of the patch elements. The overall area of the patch element is miniaturized by 50% due to the implementation of PQWIT. This miniaturized antenna is used as a radiating element for designing a beam switchable [Formula: see text] array antenna fed by a hybrid coupler. The proposed antenna prototype has been fabricated on a 1.56[Formula: see text]mm thick Rogers RT/duroid 5880 substrate with a physical area of [Formula: see text][Formula: see text]mm2. The simulation and measured results exhibit good agreements. The designed antenna offers a broad bandwidth of 844[Formula: see text]MHz (1.956–2.80[Formula: see text]GHz), peak gain of 8.86 dB, peak radiation efficiency of 99.52% and has two switchable beams in the directions [Formula: see text] and [Formula: see text]. The suggested switched beam array antenna is suitable for RFID reader applications at 2.45[Formula: see text]GHz for tracking of moving objects.

Compact Interlaced Dual Circularly Polarized Sequentially Rotated Dielectric-Resonator Antenna Array

In this study, a compact 2 × 2 interlaced sequentially rotated dual-polarized dielectric-resonator antenna array is proposed for 5.8 GHz applications. The array is composed of a novel unit elements that are made of rectangular dielectric resonator (RDR) coupled to an eye slot for generating the orthogonal modes, and to acquire circular polarization (CP) radiation. For the purpose of miniaturization and achieving dual polarized resonance, the array is fed by two interlaced ports and each port excites two radiating elements. The first port feeds horizontal elements to obtain left hand circular polarization (LHCP). The second port feeds vertical elements to obtain right hand circular polarization (RHCP). A quarter-wave length transformer is employed to reduce the attenuation and consequently increase the array gain performance. The 35 × 35 mm2 () gains were 8.4 and 8.2 dBi for port 1 and port 2, respectively, with port isolations of −33.51 dB. The design achieves a voltage standing-wave ratio (VSWR) < −10 dB and an axial ratio (AR) ˂ − 3 dB bandwidth of 2.48% (5.766 to 5.911 GHz) for LHCP at port 1 and a VSWR < −10 dB and AR ˂ −3 dB bandwidth of 2.28% (5.788 to 5.922 GHz) for RHCP at port 2. The findings of the proposed design validate its use for ISM band applications.

A Fully Integrated 3.5-/4.9-GHz Dual-Band GaN MMIC Doherty Power Amplifier Based on Multi-Resonant Circuits

In this article, a fully integrated dual-band gallium nitride (GaN) Doherty power amplifier (DPA) based on multi-resonant circuits (MRCs) is presented. A lumped T-type network in combination with the output capacitances of the main and auxiliary transistors is able to realize the quarter-wavelength transformer (QWT) in DPA, and its component values are totally decided by the operating frequency, given a certain characteristic impedance. MRCs are proposed to exhibit the required component values at two different frequencies. By replacing each component in the T-type network with an MRC, a dual-band QWT can be achieved. An integrated dual-band DPA is implemented in a commercial 0.25- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> GaN-HEMT process to validate the proposed method. The fabricated DPA shows a saturated output power of 43.8–44.7/44.4–44.8 dBm, a 6-dB back-off drain efficiency (DE) of 41%–46%/41.5%–47%, and a saturated DE of 49%–52%/56%–59% in 3.35–3.6/4.8–5.2 GHz, with a compact size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.8\times3.5$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Applying a 100-MHz OFDM signal with a 7.8-dB peak-to-average power ratio (PAPR), an average efficiency of 37%/40% and an average power of 37/37 dBm are measured at 3.5/5.0 GHz, and the adjacent channel power ratio (ACPR) is better than −49 dBc after digital predistortion (DPD). To the best of our knowledge, the proposed DPA is the first demonstration of fully integrated dual-band GaN DPAs.

A Compact Sequentially Rotated Circularly Polarized Dielectric Resonator Antenna Array

In this study, a compact 2 × 2 circularly polarized (CP) sequentially rotated (SR) dielectric resonator antenna (DRA) array operating in the IEEE 802.11a band is presented. To acquire the CP radiation, an elliptical slot (ES) was introduced to couple a rectangular dielectric resonator (RDR). The ES generates two resonant frequencies corresponding to the dominant even and odd modes. The SR feeder is made of four quarter-wavelength microstrip transformers to reduce the input impedance of the elements and, consequently, maximize the power transferred to each element. Experimental and simulation verifications were conducted on a 54 × 50 × 0.813 mm3 prototype to evaluate the performance of the proposed antenna array, which achieved a VSWR &lt; −10 dB bandwidth of 1 GHz (5.1–6.05 GHz) and axial ratio (AR) &lt; 3 dB of 0.95 GHz (5.1–5.85 GHz). The agreement between the simulated and measured results confirmed the validity of the proposed design.

Multi-way differential power divider with microstrip output interfaces

Abstract The design and implementation of planar multi-way differential power dividers remain a challenge in terms of the compactness and especially, for the achievable characteristic impedance of the quarter-wavelength transformer when considering large number of outputs. In this work, the double-sided parallel stripline is recommended to realize such a power divider with out-of-phase outputs, and explicit design methods are provided. The proposed multi-way power divider was developed without the use of lump elements on a single substrate. For system applications, a prototype operating at 41.6 MHz with 12 pairs of out-of-phase outputs that utilize the microstrip line as the output interfaces was fabricated and examined. At the center frequency of 41.6MHz, the developed prototype measured insertion losses akin to 14.3 dB as compared with the theoretical data of 13.8 dB. The attainable impedance bandwidth ranges from 10 MHz to 80 MHz under a magnitude imbalance of ±0.3 dB. The isolations of the adjacent outputs are about 13.1 dB as compared with the theoretical values of 14.428 dB, and are better than 34 dB for more distant ones. Parameter measurements are in good agreement with the numerical predications, thus demonstrating the realization of the proposed multi-way power divider.

A compact UWB monopole antenna with penta band notched characteristics

A modified rectangular monopole ultra-wideband (UWB) antenna with penta notched frequency bands is presented. An inverted U shaped and slanted U-shaped on the radiating patch are inserted to achieve WiMAX and ARN bands rejection respectively, two mirrored summation Σ-shaped and four mirrored 5-shaped slots are inserted on the partial ground to achieve WLAN and X-band bands rejection respectively, finally rectangular shaped slot with partially open on the feed is inserted to achieve ITU-8 band rejection. The proposed antenna which was simulated has a compact size 30×35×1.6 m3. It is operated with impedance bandwidth 2.8-10.6 GHz at |S11| < −10 dB, that supported UWB bandwidth with filtering the five narrowbands that avoid the possible interference with them. The simulated resonant frequency for notched filters received 3.55, 4.55, 5.53, 7.45, 8.16 GHZ, for WiMAX, ARN, WLAN, X-Band, ITU-8 respectively. The proposed antenna is suitable for wireless communication such as mobile communication and internet of everything (IoE). Throughout this paper, CST-EM software package was used for the design implementation. Surface current distributions for all notched filters were investigated and shown that it is concentrated around the feeding point and the inserted notched slots proving that there is no radiation to the space due to maximum stored electromagnetic energy around each investigated notch slot, proving that the slots play a role of a quarter wavelength transformer which generates for each notched band, maximum gain, and radiation pattern are also investigated.

Proposal and Design of a Power Divider With Wideband Power Division and Port-to-Port Isolation: A New Topology

In this article, a novel topology is proposed to design a class of power dividers with the simultaneous realization of wideband power division and port-to-port isolation. On the one hand, in order to achieve a wideband power dividing response, two wideband filtering branches, including multimode resonators and parallel-coupled lines, are formed to replace the quarter-wavelength impedance transformers in the Wilkinson power divider. On the other hand, two output ports are at first electrically connected in shunt, stretched by quarter-wavelength transmission lines and then shunt-connected via one resistor, aiming to achieve the highly desired wideband port-to-port isolation. After the theoretical analysis on frequency responses of power division and port-to-port isolation is carried out, a prototype power divider on the microstrip-line structure is designed and fabricated. Good agreement between the simulated and measured results is obtained, exhibiting an extremely wide operating band of 78% fractional bandwidth, over which 3 ± 0.3-dB power division and 17.5-dB port-to-port isolation have been simultaneously achieved.

Analysis of asymmetric coupling lines and design of a Wilkinson power divider based on harmonic suppression network

In this paper, symmetric (equal impedance lines) and asymmetric coupling lines (unequal impedance lines) are analyzed and investigated. From the research, it has been ascertained that the coupling effect in the equal impedance lines creates a new transmission zero. Also, the coupling effect in unequal impedance can control two created transmission zeros. The purpose of this work is to design a network for suppressing large numbers of harmonics with a large number of controlled transmission zeros. Therefore, a harmonic suppression network (HSN) is designed based on asymmetric coupling lines. Designed HSN generates a large number of transmission zeros with an acceptable stopband bandwidth. The proposed HSN has been replaced with two quarter-wavelength transformers in the conventional Wilkinson power divider. The number of suppressed harmonics by the HSN is greater than the number of suppressed harmonics by the quarter-wavelength, while the size of the HSN is much more compact. Also, a power divider is designed based on the proposed HSN. The designed power divider has a compact size and low insertion loss for S21 and S31 at 1.2 GHz. The number of suppressed harmonics is up to the 16 harmonic. The measured results show a frequency operation range from 0.7 to 1.26 GHz (109.6%) with a more than 10-dB return loss. The isolation in the entire operation range, agreeing well with the simulation results.

Dual-Band Microstrip Corporate Feed Network Using an Embedded Metamaterial-Based EBG

This paper demonstrates the design and experimental validation of a dual-band microstrip (MS) corporate feed network using an embedded metamaterial-based electromagnetic bandgap (MTM-EBG) structure. The MTM-EBG is designed to appear as a $35.4~\Omega $ MS transmission line (TL) with a 90° electrical length at both 2.4 and 5.0 GHz. This structure is then used in place of a conventional single-band quarter-wavelength transformer in a $50~\Omega $ MS T-junction power divider, rendering it dual band with 10 dB return-loss fractional bandwidths of 82.3% and 12.0% at center frequencies of 2.4 and 5.0 GHz, respectively. The result of this modification shows a very good performance at both operating frequencies, as well as substantial rejection over a prescribed bandwidth of intermediate frequencies. The dual-band transformer formed by the embedded MTM-EBG is 30.5% miniaturized at 2.4 GHz relative to a conventional MS quarter-wavelength transformer, which indicates its potential for use in size-restricted scenarios and embedded filtering applications. A dual-band four-way corporate feed network is then formed by cascading the MTM-EBG-loaded T-junction power dividers, which is suitable for antenna array applications. This structure has an improved performance at 2.4 and 5.0 GHz compared to unloaded networks designed for these frequencies having the same overall size. The experimental 10 dB fractional bandwidth for the MTM-EBG-loaded corporate feed network was found to be 52.0% and 10.8% around 2.4 and 5.0 GHz, respectively.

Design method of dual-band Wilkinson power divider with improved out-of-band rejection performance and high design flexibility

In this paper, a dual-band two-way equal-split Wilkinson power divider (PD) with improved out-of-band rejection and high design flexibility is proposed. The proposed structure is an originally configured impedance transformer that is composed of two impedance matching lines and a short-circuited composite right-/left handed (CRLH) transmission line (TL) stub. CRLH-TL replaces the requirement of quarter-wavelength impedance transformer and also shows the high design flexibility in proposed PDs. The characteristic impedance of composed RH-TL and LH-TL only affects the bandwidth of two pass-bands that assure high design flexibility. Whereas, π phase response in two pass-bands of short-circuited stub is attributed to the improved out-of-band rejection performance. The detailed theoretical analysis indicates the selected range of the two centre frequencies is influenced by CRLH-TL impedance matching line. The proposed dual-band PD centred at 0.90 GHz and 2.45 GHz design is theoretically calculated, simulated and fabricated. The obtained results verify that the proposed design method is having high design flexibility and good out-of-band rejection.

High Gain of Directional Ultra-Wideband Array Antenna Using Flat Reflector Structure for Microwave Imaging

UWB array antenna with high gain is proposed. The 4 × 1 array antenna consists of four identical copper circular patches are appropriately connected using quarter-wavelength transformer transmission line. The array elements and its feed network are properly optimized to have a high gain performance over wide range bandwidth frequencies. New additional flat reflector with distance of 20 mm enhances the proposed antenna gain. UWB antenna performance with reflector is better than UWB antenna without reflector structure. Antenna with reflector recorded wider operated bandwidth; 1.9GHz-10.6GHz with higher gain ranged from 3.5dB until 14.2dB compared with without reflector antenna operated from 2.2GHz to 10.6GHz with lower gain ranges of 1.9dB to 9.8dB. The reflector structure enhanced the antenna gain by 50% where the average gain throughout operated frequency for antenna with reflector and antenna without reflector is 10.2dB and 6.8dB respectively. Dimensions of 80 mm × 45 mm is considered as small UWB array antenna. The high gain and wide operator bandwidth of proposed antenna finds it very suitable to be integrated in human brain microwave imaging system due to ability of the wide signal with high energy penetrating human head structure.

Wideband Transition for Increased-Height Empty Substrate Integrated Waveguide

Recently, Empty Substrate Integrated Waveguide (ESIW) technology was proposed for embedding empty waveguides into planar substrates in order to improve their performance. A low-loss and narrow-band transition from microstrip to an increased height ESIW with 4 layers was presented in a previous work, and used to implement a very high-quality factor bandpass filter at Q-band. With such a narrow-band transition, based on a quarter-wavelength transformer, a very narrow-band filter response with resonators having a quality factor of 1000 was achieved. In this paper, in order to overcome the narrow-band and the 4-layers output restrictions, and extend the practical use of such increased height ESIWs beyond narrow-band filters, we present a novel wideband transition from microstrip to an increased height ESIW with an arbitrary number of layers. A full suite of wideband transitions to increased height ESIWs, built with different number of substrate layers ranging from 3 to 8, has been designed in this work to operate at Ka-band, though they can be easily transferred to other bands if the dimensions of the transition are properly scaled. To illustrate this, the original Ka-band transitions have been mapped to Ku-band, with excellent results. In order to test the proposed design method, a prototype of a 4-layer structure has been fabricated at Ka-band, achieving a good performance in the whole useful bandwidth of the ESIW.

Microstrip Four-Way Reconfigurable Single/Dual/Wideband Filtering Power Divider With Tunable Frequency, Bandwidth, and PDR

In this paper, a microstrip reconfigurable four-way filtering power divider (FPD) with tunable center frequency (CF), bandwidth (BW), and power division ratio (PDR) is presented. A novel coupling scheme is proposed based on four stub-loaded quad-mode resonators (SL-QMRs), two three-line coupled structures, and two quarter-wavelength transformers, which can achieve tunable CF, BW, PDR, and wide isolation BW. Switchable single/dual/wideband filtering response and the CF and BW of a dual-band FPD can be tuned by controlling the varactor diodes loaded onto the open-ends of SL-QMRs. Meanwhile, the PDR is controlled by varying the coupling strength between the center line and sidelines of a three-line coupled structure. Compared with the conventional wideband FPDs, the capacitor loaded onto the parallel coupled line of two outputs enlarges the coupling, which can improve the return loss and, thus, relieve the limitation of the line space. Based on the coupled resonator theory, the parameters of the resonators and coupling sections are analytically determined. For the dual-band FPD, the measured results show that the 3-dB fractional BW of the lower passband can be tuned from 23.4% to 30.9%, while the one of the upper passbands is tuned from 12.3% to 18.5%. The measured CF for the upper passband can be tuned independently from 1.98 to 2.21 GHz, while the lower one remains fixed. Then, the measured PDR is controlled from 1:1:1:1 to 1:2:1:2. The proposed four-way reconfigurable FPD exhibits switchless single/dual/wideband filtering responses, high isolation level, wide isolation BW, and the control of CF, BW, and PDR.

Design of inverse Class‐F power amplifier based on dual transmission line with 87.4% drain efficiency

AbstractIn this paper, an inverse Class‐F power amplifier (PA) based on dual transmission line (DTL) is presented. The output matching network (OMN) with DTL has a simple and compact circuit topology compared with other harmonic‐tuned OMNs with open/short shunt stubs and provides up to 6th harmonic suppression. In addition, the DTL structure is equivalent to a quarter wavelength transformer for fundamental matching. A GaN HEMT is adopted to achieve high output power and high drain efficiency in the proposed inverse Class‐F PA. Finally, a 2.4 GHz inverse Class‐F PA is designed and fabricated. The experimental results show the highest drain efficiency of 87.4% in the operating frequency with the corresponding output power of 44.5 dBm, and adjacent channel power ratio (ACPR) of −50.8/‐51.6 dBc with digital predistortion technique (DPD) at 2.4 GHz.

Compact Power Divider Integrated with Coupler and Microstrip Cavity Filter for X-band Surveillance Radar System

This paper present the compact power divider integrated with coupler and microstrip cavity filter for x-band surveillance radar system. These modules consist of several devices (splitter, filter and coupler) it is integrated in a single module aims to reduce the loss in the joint connectors. The bandpass filter is use microstrip cavity filter for operating on X-Band Frequency and deployed on RT/duroid 5880. The power divider and coupler is designed using quarter wavelength transformer. A theoretical analytical circuit model will be presented, from the theoretical model, a compact integrated module will be designed and simulated. The proposed compact integrated module is small in dimension and performs a compact size. The compact integrated devices design on X-Band frequency is simulated and the result is presented.

On the design of equal division single-band filtering dividers with an extended transmission line and resistor as isolation elements

This paper introduces a new scheme for effective output port isolation and return loss in RF-filtering divider design. The proposed design incorporates an extended transmission line and a conventional resistor as isolation elements. The technique has a simpler microstrip circuit implementation when it comes to the integration of a single-band band-pass filter with a Wilkinson power divider to achieve simultaneous filtering-dividing action. It is established that if a band-pass filter with a certain fractional-bandwidth is matched to 70.7 $\Omega $, a transmission line section and isolation resistor are sufficient for achieving reasonable output port return loss and isolation in the resulting filtering divider. In experimental validation, two single-band band-pass filters, namely a coupled-line filter and an open-loop coupled resonator triangular filter with center frequencies of 3 GHz and 1 GHz, respectively, effectively replace the conventional quarter-wavelength transformers for equal division of power. The proposed filtering divider structures were fabricated and a reasonable agreement was observed between respective simulated and measured S-parameter responses. The experimental results for a coupled-line filtering power divider and an open-loop triangular filtering power divider were as follows: 1 dB fractional-bandwidths of 15.3% and 12%, port isolations better than 31 dB and 20 dB, and good out-of-band performances up to 2.67f$_{0}$ and 2.85f$_{0}$, respectively.

Circularly Polarized Multi Segment Circular Fractal Array Antenna by Modified Feed Network for C-Band Application

ABSTRACTIn this paper, a novel broad band circularly polarized (CP) array antenna by modified feed network is presented. Non-using quarter wavelength transformer and focusing of feed network in centre section of array are advantages of this antenna. Moreover, employing ultra-wide band CP multi segment circular fractal structure, according to the benefits of fractals, causes to create innovation at proposed CP array antenna. Acceptable agreement between the simulation and measured results validates the proposed design. The 3-dB axial ratio of the array extends to approximately 2.3 GHz with an impedance bandwidth of 41%. The proposed array was designed to operate over the frequency range between 3.99 and 7.89 GHz corresponding to an impedance bandwidth of 65.54% for VSWR < 2 (1.98:1).