Switchable Feeding Network Research Articles

A wideband and high-gain circularly polarized reconfigurable antenna array based on the solid-state plasma

In this paper, a wideband and high-gain circularly polarized (CP) antenna array with polarization-reconfigurable characteristics is presented based on the solid-state plasma (SSP). The proposed antenna is composed of switchable rotating radiation structures and a switchable feed network by simulating the different SSP branches. To investigate the CP operating mechanism, a reconfigurable CP element is designed through characteristic mode analysis (CMA). A switchable sequential-phase feed network is then proposed which can provide separately two rotational excitations. A spoof surface plasmon polariton (SSPP) is adopted for radiation patches to improve gain and axial ratio (AR) bandwidth. Finally, a high-gain and wideband 2 × 2 CP reconfigurable antenna array is designed. This array achieves left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) modes when different SSP branches are excited. The array has an overlapped impedance bandwidth of 61.9 % (3.17 to 6.01 GHz) and an overlapped AR bandwidth of 40.2 % (4.01 to 6.03 GHz) in two CP states, and the peak gain is 11.68 dBic.

A 3-D Pattern-Reconfigurable Antenna Array With Multipolarization

In this letter, a 3-D pattern reconfigurable antenna array with multi-polarization is presented. It comprises four vertically placed reconfigurable end-fire dipole-pair elements and a compact four-path switchable feed network. By utilizing switchable operating dipoles of each element and appropriate pathways on the feed network, the antenna can achieve adaptive control of broadside patterns and backfire patterns with independent left-handed/right-handed circular polarization (LHCP/RHCP) and ±45° linear polarization (LP) in the elevation plane. Moreover, four end-fire patterns with vertical polarization (VP) can be adaptively controlled in the azimuth plane. The proposed antenna is fabricated and measured. With a compact 3-D structure of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>$0.49\lambda_0 \times 0.49\lambda_0 \times 0.39\lambda_0$</tex-math></inline-formula> , the measured -10 dB overlapped impedance band for the twelve operating states is 2.3 GHz-2.75 GHz (17.8%). Besides, the corresponding crosspolarization discrimination (XPD) is more than 17.4 dB.

Wideband Quad-Polarization-Reconfigurable Bidirectional Antenna With a Simple Wideband Switchable Feeding Network

This paper presents a wideband quad-polarization-reconfigurable bidirectional antenna using a simple wideband switchable feeding network. By cutting a symmetrical fractal slot on the ground, a wideband dual-polarized differential bidirectional circular monopole antenna with high isolation is realized. To achieve reconfigurable quad-polarization diversity, the bidirectional circular monopole antenna is fed by a wideband switchable feeding network, which provides four output states by only using six PIN diodes. For verification, a prototype operating at 1.85 GHz is designed and fabricated. For the two linear polarization (LP) states, the measured 10-dB bandwidths are 28.4% and 25.3%, while the measured peak gains are 4.2 dBi and 3.1 dBi, respectively. For the two circular polarization (CP) states, the measured bandwidths with 10-dB return loss and 3-dB axial ratio (AR) are 26.3% and 17.4%, respectively. The measured peak gains are 2.8 dBi and 2.4 dBi, respectively.

A first‐harmonic push–push oscillator based active integrated dual‐beam switchable array antenna

This paper proposes a new active integrated array antenna (AIAA) for dual-beam switchable functionality. The proposed AIAA comprises a first-harmonic push–push oscillator, four linearly polarized microstrip antennas, and a switchable feed network. The first-harmonic push–push oscillator eliminates the impact of load variation and usage of a filter to suppress the second- and higher-harmonic frequency signals. By using the switchable feed network, the main beam direction of the radiation pattern can be switched between two states, i.e. θ = ± 10 ∘ $\mathbf {\theta = \pm }10\mathbf {^{\circ }}$ . The performance of the proposed antenna is experimentally evaluated. The measured results show an effective isotropic radiated power (EIRP) of +27.5 dBm, DC-to-RF efficiency of 20.26%, and figure of merit (FOM) of −155.2 dBc Hz−1 at the fundamental frequency of 5.9 GHz.

Wideband Polarization Agile Dielectric Resonator Antenna With Reconfigurable Broadside and Conical Beams

A new broadside and conical beam reconfigurable dielectric resonator antenna (DRA) with three orthogonal linear polarizations (LPs) and two orthogonal circular polarizations (CPs) agility is presented. It consists of a quad-strip-fed DRA element and a reconfigurable feeding network. First, the DRA element is designed to make unidirectional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm{HEM}}_{11 \delta }$ </tex-math></inline-formula> mode and omnidirectional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm{TM}}_{01 \delta }$ </tex-math></inline-formula> mode operate in the same wide band by tactfully removing a concentric annular column from its interior. Furthermore, a center-loaded metal post helps to improve the impedance matching of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm{TM}}_{01 \delta }$ </tex-math></inline-formula> resonance significantly. Afterward, the switchable feed network is designed to implement diverse phase distributions of four output ports, i.e., providing the quad-port in-phase excitation, dual-port differential excitations, and quad-port sequentially rotated phase excitation strategies for a vertical LP, ±45° slant horizontal LPs, and two CPs, respectively. Finally, a fully functional prototype is designed, fabricated, and measured to validate the design. The measured results show that the overlapping impedance bandwidth of 36.8% for all the states and the axial-ratio bandwidth of 33.8% for the CPs are obtained.

An Electrically Controlled Pattern- and Polarization-Reconfigurable Cylindrical Dielectric Resonator Antenna

A pattern- and polarization-reconfigurable dielectric resonator antenna (DRA) is presented. It deploys a conventional cylindrical dielectric resonator (DR) with a new switchable feeding network. The feeding network has four slots that are etched in the ground. By tuning the phase distributions in these slots, three DR modes (the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01δ</sub> and two degenerated HEM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sub> modes) are excited. The former has an omnidirectional radiation pattern, whereas the latter two have boresight patterns with orthogonal polarizations ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -polarization). By tuning the height-to-radius ratio, these modes can be designed to operate at the same frequency, thus enabling both the pattern and polarization reconfigurability. A prototype of the reconfigurable DRA working in 2.4 GHz is fabricated and measured to verify ideas. Reasonable agreement between measurements and simulations is obtained. Our design provides both pattern and polarization reconfigurability, with good efficiency in the band of interest.

A quadrature‐hybrid‐integrated reconfigurable feeding network for wideband quad‐polarization‐agile antenna design

In this article, a reconfigurable antenna with quad-polarization radiations is proposed based on a switchable feeding network. A wideband quad-mode feeding network is first designed by integrating a simple impedance converter with a modified hybrid coupler. By switching the p-i-n diodes, four-transmission status with specific amplitudes and phase differences at feeding output ports can be obtained over a wide frequency range, hence enhancing the radiating bandwidth of two linear and two circular polarizations. Finally, a prototype of the proposed quad-polarization-agile reconfigurable antenna is designed and fabricated. The measured results show a wide overlapped bandwidth of 782 to 1010 MHz (25.4%) for all four polarizations with a competitive size and gain performance.

A design for pattern reconfigurable antenna systems

AbstractA pattern reconfigurable antenna system is presented. The system is composed of a cubic array excited with a switchable feed network, a microcontroller (MCU), and a mobile application (app). The cubic array has five radiating elements, and the active state of each element is controlled by the switchable feed network. Simulated results show that the array integrated with the feed network can provide five high‐directivity scanned beams, 11 unidirectional patterns with wide beamwidth, two bidirectional patterns, and one omnidirectional pattern. For promptly switching among these radiation patterns, a MCU is used to manage the DC voltages of PIN diodes in the feed network. In addition, the used MCU has a Wi‐Fi module, and it can communicate with a mobile device through wireless area local networks. Consequently, the pattern switching can be realized with remote control. Details of system designs are described. Measured results for the array and feed network are also given.

Embedded Design of Compact Broadband Omnidirectional Antenna With Quad-Polarization Diversity

A compact and broadband omnidirectional antenna is proposed for quad-polarization diversity. Novel reconfigurable structures of omnidirectional vertical polarization (VP) and horizontal polarization (HP) elements based on embedded design are put forward to achieve low-profile. A simplified equivalent LC cascaded circuit is modeled to better understand the broadband VP element and guide its design. In order to realize quad-polarization diversity, an advanced switchable feed network, which contains ten p-i-n diodes with four output states are carefully designed. Measured results show that the overlapped bandwidth for all operation modes is 20.5% (2.28–2.8 GHz) within a compact size of 0.69 λ 0 × 0.69 λ 0 × 0.064 λ 0, where λ 0 is the free-space wavelength at the center frequency 2.5 GHz.

A 16‐element array fed with a switchable power divider

AbstractA pattern reconfigurable design realized by a planar array integrated with a switchable feed network is presented. The array has 16 radiating elements, and each element is a printed dipole backed with a metallic box. These elements are divided into four groups, and the excitation state of each group can be controlled with the feed network. By varying the number of the active groups, the radiation pattern of the array is reconfigured. Simulated results demonstrate that the proposed array can generate broadside beams with a front‐to‐back ratio of higher than 25 dB, and the half‐power beamwidths of these main beams in E‐plane or H‐plane can be switched among 20°, 26°, and 46°; besides, the array can produce three different side lobe levels, including −1, −12, and − 25 dB, in the two principal planes. For the proposed pattern reconfigurable array, a prototype is constructed, and its experimental results are also exhibited to validate the simulated data.

Design of a Quad-Polarization-Agile Antenna Using a Switchable Impedance Converter

This letter presents a novel quad-polarization-agile aperture-coupled antenna using a reconfigurable impedance converter. The designed reconfigurable converter can achieve impedance and phase changes under the control of p-i-n diodes. Based on this converter, a quad-mode switchable feeding network can be produced. Utilizing the feeding network to excite a dual-polarized aperture-coupled patch antenna, polarization reconfigurability is realized. By switching the p-i-n diodes, two orthogonal linear polarizations (LPs) and two orthogonal circular polarizations can be generated. Measurement results show that its return-loss bandwidth is wider than 2.5% at LP modes, its axial-ratio bandwidth is better than 1.8%, and its cross polarizations are below -20 dB for all the states.

Polarization and Pattern Reconfigurable Cuboid Quadrifilar Helical Antenna

A novel cuboid quadrifilar helical antenna (QHA) with polarization and pattern reconfigurabilities is presented. The proposed antenna consists of a reconfigurable radiator and a switchable feeding network. The radiator combines two individual QHAs in a cuboid, which can be alternatively activated. The feeding network provides switchable quadrature excitations to the radiator. By controlling the p-i-n diodes on the radiator and the feeding network, four working states including both polarization and pattern agilities are achieved. The polarization of the antenna can be switched between two orthogonal circular polarizations, and the radiation pattern can be changed between broadside and backfire modes. A prototype designed to operate at 0.9 GHz band is developed and measured. The measured results validated that the antenna achieved the four working states with stable wide-beam radiation patterns. Moreover, the proposed antenna obtained wide impedance and axial-ratio bandwidths (36.2% and 22%, respectively) in a compact size ( $0.26\lambda _{0}\times 0.26\lambda _{0}\times 0.25\lambda _{0}$ ). The proposed antenna which has attractive electrical characteristics can be applied to various wireless communications, e.g., RFID readers, subway, and railway communications.

Wideband Reconfigurable Crossed-Dipole Antenna With Quad-Polarization Diversity

A design for antennas with quad-polarization diversity is described. The antenna structure is mainly composed of a reconfigurable crossed-dipole fed with coaxial baluns and a switchable feeding network. By controlling the states of p-i-n diodes embedded in the balun feeds, the crossed dipole can generate vertical and horizontal polarization radiations, and the phase of each polarization mode can be switched between 0° and 180°. As for the feeding network, it has four output ports and only two output ports are set to be active to excite the crossed dipole at a time. By integrating the crossed dipole with the feeding network, the resultant antenna can provide four polarization modes, including ±45° linear polarizations (LPs) and dual-orthogonal circular polarizations (CPs). Moreover, the overlapped operation bandwidth of the four polarization modes is more than 35%, and within the bandwidth, the cross polarization level of the LP modes is less than −20 dB and the axial ratio of the CP modes is smaller than 3 dB. Good impedance matching is also achieved for each polarization mode.

Circularly Polarized Antenna With Reconfigurable Broadside and Conical Beams Facilitated by a Mode Switchable Feed Network

A pattern-reconfigurable slot-augmented patch antenna is reported that radiates circularly polarized (CP) fields and is switchable between a broadside and a conical radiating mode. Two novel design strategies were adopted to realize these advantageous performance characteristics. First, a mode switchable feed network which includes a set of eight L-probes was developed that facilitates the proper excitation of either the patch’s TM11 or TM21 mode and yields symmetric radiation patterns. Second, their operating bands were made to overlap by augmenting this patch with an annular slot. Consequently, the radiation pattern is easily switched between the broadside and the conical modes within the overlapping operational bandwidths. A prototype was fabricated and tested. The measured results are in good agreement with their simulated values, verifying the design concepts. The measured operating bandwidth, 7.8% from 2.45 to 2.65 GHz, was determined from the overlap of the impedance and axial ratio bandwidths for both modes. The measured realized gain values are stable for both radiating states within this operational bandwidth, the broadside (conical) peak value being 8.5 dBic (5.8 dBic). The CP pattern reconfigurability of this antenna with its favorable performance characteristics makes it an ideal candidate for many RFID and satellite communication applications.

Wideband Quad-Polarization Reconfigurable Antenna Using Switchable Feed Network With Stable Unidirectional Radiation Patterns

A wideband antenna with quad-polarization reconfigurable operation is proposed. It consists of a crossed tri-port feed linearly polarized (LP) radiation structure and a switchable feed network. A dual-port LP element with wideband characteristic and good port isolation is first introduced. The inherent 180° phase difference (PD) between two feed ports vastly simplifies the complexity of the design and improves the efficiency of the feed network. By assembling two grooved LP elements, the crossed tri-port feed radiation structure is formed. Meanwhile, a wideband 90° phase shifter and an unequal Wilkinson power divider are applied in designing the switchable feed network. Through controlling the PIN diodes implanted in the feed line, four working modes with equal amplitude and reconfigurable PD (0° or 90°) are achieved. Based on this, the desired quad-polarization reconfiguration, including two orthogonal linear polarization (LP) states and two orthogonal circular polarization (CP) states, is realized. Measured results show that the proposed antenna has a wide overlapped operation impedance bandwidth of 84.5%, ranging from 1.36 ~ 3.35 GHz, for all polarization states within a compact volume. The measured 3-dB AR bandwidth is 100%, covering the operation impedance frequency range. Radiation patterns exhibit unidirectional and stable quality from the point view of beam slant and split. Besides, a peak efficiency of 75% and a peak gain of 7.8 dBi are achieved.

Broadband Pattern Diversity Patch Antenna With Switchable Feeding Network

A single-feed wideband pattern diversity antenna is presented in this paper. The pattern reconfigurability is realized by a p-i-n-diodes-intergrated switchable feeding network with the ability of providing 0° in-phase or 180° out-of-phase antenna excitation. The radiating patch is excited by the feeding network through a pair of symmetric stepped probes. When the two stepped probes are with in-phase excitation, a conical mode can be generated on the patch. On the other hand, the antenna can operate at a broadside mode if the excitation is out-of-phase. A meticulous prototype is developed, manufactured, and measured. The measured impedance bandwidths of the 10-dB return loss are 60.7% from 1.95 to 3.65 GHz for the broadside mode and 72.7% from 1.65 to 3.65 GHz for the conical mode. Meanwhile, measured peak gains of up to 10.2 and 7.7 dBi and measured radiation efficiencies of higher than 80% and 76% are obtained for the broadside mode and conical mode, respectively.

A Polarization Reconfigurable Slot Antenna with a Novel Switchable Feeding Network

AbstractA polarization reconfigurable slot antenna is proposed in this paper. The antenna consists of a microstrip line-to-slotline transition structure, two radiation slots and a switchable feeding network. The feeding network is a gradually changed ring slot with six switching diodes on it. By controlling the diodes states, the antenna can generate y-direction polarization, z-direction polarization, left-hand circular polarization and right-hand circular polarization. Detailed design considerations of the proposed antenna, simulated and measured results are presented and discussed. Measured results agree well with simulated. The results proved that the antenna can realize polarization reconfiguration effectively at 5 GHz.

Design of a High Directive Gain Reconfigurable Circular Patch Antenna

A new probe-fed patch antenna polarization reconfiguration is presented in this proposed work. The antenna is composed of a circular radiating patch and a switchable feed network. By controlling the operating states of four pairs of pin diode in the feed network, the feed point of the circular patch can be switched. Therefore, a reconfiguration between four linear polarization directions at a 45 degree interval (22.5 degree, 67.5 degree, 112.5 degree and 157.5 degree) can be realized. All the different polarization states own similar matching and radiation characteristics. Simulated and measured results indicate that antenna can achieve reconfigurable quadri-polarization diversity features with an invariable operating frequency and excellent radiation performance, which are very attractive for wireless communications. In addition, the proposed design can offer more reconfigurable linear polarization directions by adding more switchable paths in the feed network.

Multipolarization-Reconfigurable Circular Patch Antenna With L-Shaped Probes

This letter introduces a multipolarization-reconfigurable circular patch antenna with eight L-shaped probes. By adopting the L-probe feeding structure, the reported circular patch antenna is compact, simple, and low-profile. It has switchable 0°, +45°, 90°, and -45° linear polarizations and is able to mitigate the polarization mismatch problem in complex wireless channels. This polarization reconfigurability is realized by controlling a set of p-i-n diodes via a switchable feeding network. Measured results show that the antenna has excellent electrical performance for all operating states. The overlapping impedance bandwidth (when the reflection coefficient ≤ -10 dB) is 17.6%, from 2.325 to 2.775 GHz, which covers both the WLAN and ISM bands. The gain is very stable across the entire bandwidth with a 6.1-dBi peak value, and the cross-polarization levels are low. Moreover, good cardioid-shaped radiation patterns are attained.

High‐gain polarization‐reconfigurable monopole antenna for GNSS applications

ABSTRACT:The design of a circular polarization (CP) reconfigurable monopole antenna with enhanced boresight gain for the Global Navigation Satellite System (GNSS) is presented. The antenna is composed of two meandered monopoles perpendicular to each other, a switchable feeding network and a metallic reflector. The switchable feeding network consists of a Wilkinson power divider, a 90°‐phase shifter, a double‐pole double‐throw (DPDT) switch, and a defected ground structure (DGS). The power divider divides the input signal into two signals with equal amplitude and 90°‐phase difference. The two signals arrived at the two monopoles have a phase difference of 90° or −90°, determined by two DC voltage inputs to the DPDT switch hence to generate a right‐ or left‐handed CP signal. Compared with the previous work, the antenna requires only two control DC voltages and so is much simpler. Measured results show that the metallic reflector placed at the back of the antenna increases the boresight gain by 5 dBi. The measured impedance bandwidth (S11&lt; −10 dB) and axial‐ratio bandwidth (AR&lt; 3 dB) are from 1.28 to 1.97 GHz and 1.44 to 1.85 GHz, respectively. Simulated and measured results on S11, AR, radiation pattern, and gain show good agreements. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:791–798, 2016