Line Feed Network Research Articles

Design of a Low Sidelobe Feed Network Based on the Louver-Shaped Defected Ground Structure

In this paper, a low sidelobe feeding network has been developed utilizing the louver-shaped defected ground structure (DGS). By adjusting the louver-shaped DGS, the output amplitude and phase of the corresponding ports can be altered, minimizing deviations from theoretical values. This enables antenna arrays equipped with this feeding network to more easily achieve low sidelobe performance. The impact of the louver-shaped DGS on the amplitude and phase of each port in the power divider within the feeding network is analyzed, and a 16-channel feeding network incorporating the louver-shaped DGS has been designed, fabricated, and then measured. The test results indicate that the performance of the line-feeding network is effectively improved by designing and adjusting the louver-shaped DGS. Through the debugging procedure, the amplitude deviation of the feeding network has been reduced from ±0.45 dB to ±0.2 dB, while the phase deviation of the feeding network has been reduced from ±8° to ±2.5°, and the maximum value of the first sidelobe has been reduced from −24.2 dB to −28.1 dB.

3-D SISL Feeding Network for 2-D Cavity-Backed Endfire Dipole Array at 24 GHz

This letter presents a 4×4 cavity-backed endfire dipole array with a novel feeding structure named as three-dimensional substrate integrated suspended line (SISL) feeding network (TSISLFN). Based on the SISL's structural superiority, air-filled substrate integrate waveguide (AF-SIW) can be vertically integrated with planar SISL in a self-packaged manner to form the TSISLFN. TSISLFN can be easily integrated with 2-D cavity-backed dipole array and the overall architecture can be realized through printed circuit board (PCB) technology. Then, the cost and weight of the whole structure are significantly reduced compared to the metal-waveguide counterpart. TSISLFN possess merits of self-packaging, low cost, and low loss. Both 2×2 and 4×4 cavity-backed endfire dipole arrays fed by TSISLFN are fabricated and measured. At 24.5 GHz, high efficiency of better than 91% and 79%, gain of 15.2 and 20.6 dBi are all obtained for the proposed 2×2 and 4×4 array respectively. Similar narrow beam widths in both E and H planes are also obtained.

A Wideband Compact Printed Dipole Antenna Array With SICL Feeding Network for 5G Application

A wideband compact printed dipole antenna array with an element size of 0.16 λ0 × 0.34 λ0 is proposed for millimeter-wave (mmW) applications, particularly for 5G applications. The two patches of the dipole are printed on two different layers to achieve a wide bandwidth of 50% (24–40 GHz) for SWR <2. Ground-signal-ground transmission line construction with a height difference between the feeding via and the two shorting vias is employed to achieve a relatively symmetrical radiation pattern. An antenna array consisting of the proposed antenna and a 1 to 8 substrate-integrated coaxial line feeding network is fabricated and measured. Simulations are also used to verify the beam scanning performance (up to ±50°). The proposed compact printed dipole antenna is a good contender for 5G mmW applications due to its wide band, compact size, and good beam scanning performance.

A Wideband Compact Magnetoelectric Dipole Antenna Fed by SICL for Millimeter Wave Applications

A wideband compact magnetoelectric (ME) dipole antenna is investigated for millimeter-wave applications. First, an aperture coupled ME dipole is proposed with wideband and low profile. Next, transverse slots are added to miniaturize the antenna. The radiation performance of the higher-order mode is also improved. The antenna is finally miniaturized to 2.5×3.3 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ( 0.27 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.35 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength in free space at center frequency) when it is used in the array environment. A bandwidth of 48.8% (24.3-40 GHz) for SWR <; 2 can be achieved, with unidirectional radiation performance over the operating band. By combining the proposed compact antenna with an eight-way substrate integrated coaxial line (SICL) feed network, a 1 ×8 linear array is designed, fabricated, and measured. Good beam scanning capability is also verified by active simulation. With the advantages of wide bandwidth, compact size, promising radiation pattern and wide-angle beam scanning potential, the proposed antenna would be attractive for millimeter-wave devices and antenna in package (AiP) applications.

A Miniaturized Broadband and High Gain Planar Vivaldi Antenna for Future Wireless Communication Applications

This paper presents a new miniaturized planar Vivaldi antenna (PVA) design. The proposed antenna structure consists of an aperture tapered profile and cavity stub fed with a simple 50 Ω strip line feeding network. The designed PVA offers versatile advantages, including the miniaturized size and simple design, and exhibited an outstanding performance compared to the latest reported literature. The antenna occupies a minimal space with an electrical size of 0.92λ0 × 0.64λ0 × 0.03λ0. The antenna achieves an excellent relative impedance bandwidth 117.25% at 10 dB return loss, peak realized gain of 10.9 dBi, and an excellent radiation efficiency of 95% at the specific resonances. The antenna’s optimal features, that is, broadband, high gain, and radiation efficiency, are achieved with efficient grooves based approach. Besides, the proposed antenna results are also analyzed in the time domain, which shows the excellent group delay performance &lt;2 ns in the operational band. The proposed antenna exhibited a stable far-field radiation pattern in orthogonal planes and strong distribution of current at multiple resonances. Simulation and the measured result show a good agreement. The proposed antenna has achieved optimal performance and is suitable for future wireless communication applications.

A Broadband High-Gain Printed Antenna Array Using Dipole and Loop Patches for 5G Communication Systems

A broadband and high-gain printed antenna array is presented in this paper. Its single antenna element consists of a loop and two symmetric dipole patches, making the element exhibiting broad impedance bandwidth and improved gain at the targeted frequency, which is 28 GHz, one of the 5G mm-wave band, for this design. An 8×3 antenna array fed by a microstrip line feed network was designed and simulated. With a compact size of 98×32.5 mm2 , the array presents a broad -10 dB impedance bandwidth of 6.8 GHz (24.3%) and a high gain of 18 dBi at 28 GHz. Besides, the single-layered array also features low profile, simple geometry, and low cost, making it a good candidate for 5G communication systems.

A High-Gain Millimeter-Wave Magnetoelectric Dipole Array With Packaged Microstrip Line Feed Network

A millimeter-wave 4 × 4 magnetoelectric (ME) dipole antenna array using a packaged microstrip line feed network is proposed. This antenna array features a wide impedance bandwidth of more than 50% and small back radiation. Each ME dipole element is excited by an L -shaped probe and each L -shaped probe is connected to the packaged microstrip line through a small hole in the ground plane. The packaged microstrip line forms the whole corporate feed network for the antenna array. The entire antenna structure is realized by multiple printed circuit boards (PCBs), which is low in material cost and easy in fabrication. The results demonstrate that the proposed antenna array enables the impedance bandwidth of 51.5%, high gain up to 20.3 dBi, and stable broadside radiation pattern with small back radiation over the operating frequencies. The array is suitable for the 5G application.

Packaged Microstrip Line Feed Network on a Single Surface for Dual-Polarized 2N×2M ME-Dipole Antenna Array

A packaged microstrip line feed network on a single substrate surface is presented in the Ka-band for a 4 × 4 dual-polarized array with a capability to be expanded to higher order 2N × 2M, where N and M are integer numbers larger than 1. A dual-polarized aperture-coupled magneto-electric dipole antenna is designed as a single element with 20% bandwidth of −10 dB reflection coefficients, ports’ isolation better than 35 dB, cross polarization less than −25 dB within the main beam view-range of 30°, and gain of 8 dBi. A 4 × 4 array is implemented that maintains a bandwidth of 16.7% at 30 GHz with a maximum gain of 19.3 dBi.

Design of Reconfigurable Stacked Patch Microstrip Antenna (RSPMA) at 1.8 GHz and 2.3 GHz

This paper presents a Reconfigurable Stacked Patch Microstrip Antenna (RSPMA) uses a combination of aperture coupled technique and stacked patch technology for reducing feigned radiation patterns. This RSPMA consists of three FR-4 substrate layers with 4.7 mm thickness each and 3 mm thick of an air-filled substrate between stacked patches and the ground plane. The top patches are rectangular shaped with a T-shaped hole at the center and the bottom patches are T-shaped, both etched on top of substrate 1 and substrate 2 respectively act as a radiating element. Two H-shape designs of aperture slots of different sizes on the ground plane are positioned at the center of the ground plane with reference to the top patches and bottom patches. A copper strip is used as an ideal RF switch is implemented at the feed line network for the ON and OFF mode. Thus, by adjusting the switch mode, the resonance frequencies can be varied, thus frequency reconfigurable is achieved. The activation of the selected aperture slots will produce waves and radiates the signal to the radiating layers of the patch antenna. Hence, two different frequencies, either at 1.8 GHz or 2.3 GHz were achieved through the RSPMA with the gain of 3.691 dB and 2.291 dB, respectively. The antenna designed was simulated using CST Microwave Studio at an operating frequency of 1 GHz to 2.7 GHz. The RSPMA is said to be potentially beneficial to the wireless communication system.

Broadband Endfire Magnetoelectric Dipole Antenna Array Using SICL Feeding Network for 5G Millimeter-Wave Applications

A broadband endfire antenna array is investigated for 5G millimeter-wave applications. First, an improved magnetoelectric (ME) dipole with a defected ground structure is proposed, which is excited by a planar L-probe. This proposed ME-dipole antenna shows stable radiation during the relative bandwidth of 53.0%. Next, a 16-way substrateintegrated coaxial line (SICL) feeding network is presented. Its bandwidth is 109.5% for |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | ≤ -15 dB and insertion loss is less than 13.4 dB. This full-corporate SICL feeding scheme is utilized to construct the broadband antenna array. Finally, the proposed antenna array is fabricated and its performance is evaluated. Considering the impedance bandwidth for |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | ≤ -10 dB, the 3 dB gain bandwidth, and the radiation efficiency, the overall measured operating bandwidth is 50.7%, which covers two main candidate frequency bands of 28 and 39 GHz. The cross-polarization level is less than -19.0 dB and the front-to-back ratio is better than 20.0 dB in the whole operating bandwidth. Additionally, a 4 × 4 2-D multibeam array is also simulated to verify the beamforming potential of the proposed antenna array.

Millimeter-Wave Beam-Steering Focal Plane Arrays With Microfluidically Switched Feed Networks

Microfluidically switched feed networks are introduced to realize millimeter-wave beam-steering focal plane arrays (FPAs). Switching functionality is achieved by a selectively metallized plate (SMP) repositionable within a microfluidic channel that is brought in close proximity to the microstrip line feed network of an FPA. The feed network is strategically designed to exhibit gap discontinuities that are sequentially overlapped by the SMP metallizations. The capacitive couplings between the SMP metallizations and the gap discontinuities are designed to achieve wideband (~20 GHz) switching functionality with low insertion loss (IL $10\times $ lower than that of the prior work. This allows to achieve a faster beam-steering speed (0.27 s versus 5.25 s of previous designs). An integrated sensing approach for detecting the SMP position is also presented for the first time to facilitate the use of presented MFPAs with closed-loop position control.

Multiple Fan-Beam Antenna Array for Massive MIMO Applications

In this paper, a multiple fan-beam antenna array is proposed for massive multiple-input multipleoutput (MIMO) applications. The proposed array is based on vertical spatial filtering to reduce radio frequency complexity in a massive MIMO system. A microstrip line feeding network is utilized to achieve a specific phase distribution for multiple fan beams. A 64-element antenna array is designed and fabricated to validate the design strategy. The proposed antenna array uses 16 ports to excite 64 antenna elements, which is more cost effective than traditional massive MIMO systems. The measured results demonstrate that the proposed antenna array can achieve two fan beams at 7 in the vertical dimension, and the measured gain of every port exceeds 10 dBi at 2.6 GHz.

High efficiency broadband ellipse antenna array with tapered parallel-double transmission line feed network

High efficiency broadband ellipse antenna array with tapered parallel-double transmission line feed network

A C‐shaped dielectric resonator antenna with frequency reconfigurable for ISM and LTE band applications

ABSTRACTA frequency tunable dielectric resonator antenna (DRA) is studied and presented for ISM and LTE band applications. Here, the frequency operation of the proposed DRA is switched from dual band to narrowband mode by using the PIN diode switches. The switches are employed by RF PIN diodes and placed on the feed line network to excite the dielectric resonator (DR). The proposed reconfigurable DRA has a compact size with a thickness of 3 mm and the overall size of 30 × 37 mm2 that is proper for mobile devices. The measured and simulated results indicate that the proposed DRA provides a single and dual band modes which covers the ISM applications and 2.6 GHz LTE system, respectively. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:134–138, 2017

Microfluidically Reconfigured Wideband Frequency-Tunable Liquid-Metal Monopole Antenna

A microfluidically reconfigured wideband frequency-tunable liquid-metal monopole antenna is presented. The antenna operation relies on continuous moving of the liquid-metal volume over the capacitively coupled microstrip line feed network with a micropump unit. To maximize the capacitive coupling at the feed point, the antenna is realized by bonding microfluidic channel molds prepared in polydimethylsiloxane (PDMS) polymer with 1-mil-thick liquid crystal polymer (LCP) substrate. The concept is demonstrated through the design and experimentation of a 4:1 frequency-tunable monopole antenna that operates from 1.29 to 5.17 GHz. The presented monopole antenna can also be utilized as an element to form wideband frequency-tunable high-gain antenna apertures without necessitating any additional micropump units. This is accomplished by resorting to strategically meandered or interconnected microfluidic channels. This concept is demonstrated through the design and experimentation of a $4 \times 1$ microfluidically controlled monopole array capable of providing 2:1 frequency tuning range from 2.5 to 5 GHz.

Flexible printed chipless RFID tag using metamaterial–split ring resonator

An 8-bit passive chipless RFID using metamaterial structure with dimension of 25 × 50 mm which operates between 3.4 and 7.4 GHz is proposed. The chipless RFID is designed using complementary split ring resonator (SRR) with a transmission line feeding network of 50 Ω. The modified complementary split ring resonator (MCSRR) is located at the backside of the substrate. The MCSRR has narrow bandwidth which can maximize the amount of bit capacity. To enhance the bit capacity, the frequency shifting is introduced by the allocation of bit conditions (00, 01, 10 and 11) at the specific resonance frequency. The polyethylene terephthalate material with e r = 3.0 and tan δ = 0.002 is a suitable candidate for body identification due to the flexibility and the robustness of the material.

Micromachined 60 GHz postsupported patch antenna with flip‐chip interconnect

ABSTRACT:This letter presents the design of a micromachined patch antenna operating at 60‐GHz band. The radiating patch and the feedline network are designed on the quartz glass (SiO2) and silicon (Si) substrate layers, respectively. An air gap, which is supported by four nonconductive posts and one solder ball, is added between the two substrate layers to reduce dielectric loss. The utilization of transparent quartz glass is helpful in alignment, and the feedline network is universal in patch array design. A 1 × 2 patch array is designed to verify the concept of array design. The measured −10 dB bandwidth of the proposed array is 2.7 GHz (56.5–59.2 GHz). © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2706–2710, 2015

A Compact Frequency-Reconfigurable Dielectric Resonator Antenna for LTE/WWAN and WLAN Applications

A compact frequency-reconfigurable dielectric resonator antenna (DRA) for LTE/WWAN and WLAN applications is investigated and presented. The proposed antenna provides the frequency tuning between 1.60 and 2.71 GHz. The design consists of four identical rectangular dielectric resonators with permittivity of 10 each and three p-i-n diode switches that are located on the feedline network between each of two dielectric resonators. The proposed antenna size is $20 \times 36 \times 5.57~\hbox{mm}^3$ , which is suitable for mobile devices. The measurement and simulation results are applied to demonstrate the performance of the proposed antenna. From the measured results, it is found that the proposed antenna with acceptable performance provides four single-band modes with the impedance bandwidths of 17%, 11%, 14%, and 6%.

Electrically Large Zero-Phase-Shift Line Grid-Array UHF Near-Field RFID Reader Antenna

A grid-array antenna using a zero-phase-shift (ZPS) line is proposed to enlarge the interrogation zone of a reader antenna for near-field ultra-high-frequency (UHF) radio frequency identification (RFID) system. The proposed grid-array antenna is composed of a number of grid cells and a double-sided parallel-strip line feeding network. Each grid cell, namely segmented loop constructed by the ZPS line, has uniform and single-direction flowing current along the line. By configuration of the cells sharing a common side with its adjacent grid cells which carry reverse-direction flowing current, a grid-array antenna is formed to generate a strong and uniform magnetic-field distribution over a large interrogation zone even when the perimeter of the interrogation zone reaches up to 3λ (where λ is the operating wavelength in free space) or larger. As an example, a grid-array antenna with 1 × 2 segmented ZPS line loop cells implemented onto a piece of FR4 printed board (PCB) is designed and prototyped. The results show that the grid-array antenna achieves the impedance matching over the frequency range from 790 to 1040 MHz and produces strong and uniform magnetic-field distribution over an interrogation zone of 308 mm × 150 mm.

Wideband ring-slot coupled patch antenna with enhanced gain

A wideband ring-slot coupled patch antenna is presented in this paper. A microstrip line feeding network is used for impedance matching. Additionally, in order to depress the backward radiation caused by the resonance of the ring-slot, a reflector is introduced to obtain unidirectional radiation patterns, while a dielectric cover is adopted to alleviate the deterioration in impedance caused by the reflector. A prototype is fabricated and measured. The measured results are in good agreement with those simulated, which indicates that the antenna operates well with a relative bandwidth of 55% for reflection coefficient less than −10 dB, an enhanced gain of 8–11 dBi, unidirectional radiation patterns, as well as low cross-polarization.