Feeding Network Of Antenna Array Research Articles

Packaged Filtering Power Divider With High Selectivity, Extended Stopband and Wideband Isolation

A packaged filtering power divider (FPD) is presented, investigated and synthesized. The radiation loss and electromagnetic interference are reduced since the FPD is insulated in a completely enclosed substrate-integrated cavity. The isolation performance and transmission property of the proposed FPD are determined by the odd- and even-mode equivalent circuit, respectively. A 3rd-order quasi-elliptic filtering response is attained by the multi-mode filtering sections composed of doubly-stub-loaded parallel-coupled lines. Five extra TZs are generated by both the central-loading (CL) T-shaped stub and side-loading (SL) short-circuited 180° and open-circuited 90° branches, which further improves the selectivity of the passband and suppresses the higher-order harmonics. Two isolation resistors are elaborately placed between the two power-division paths, which significantly improves the isolation level over the whole passband and stopband. The design equations including the position of the TPs and TZs, and the values of the isolation resistors are derived in the synthesis procedure. For verification, an FPD prototype is designed, simulated, and measured. It exhibits advantages in terms of low loss, sharp band-edge skirts as well as wideband rejection and isolation, which is suitable for IoT (Internet of Things) applications and antenna-array feeding networks.

Wideband Calibration Network for Multichannel Antenna Array Feeding Network

In this letter, a wideband calibration network using multilayer coupler is proposed for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> -band antenna array feeding network. A high performance coupler is designed to ensure consistency for the coupling of the series-fed structure. By using a serpentine feedline and making all channels the same length, phase imbalance is decreased. To reduce lateral leakage, cross-talk and mutual coupling, the vias-shielded structure and metal spacer are used. To validate the proposed calibration network design, a wideband calibration network is fabricated and measured. Measured results show that the coupling amplitude fluctuates mainly in the range of 29–37 dB with phase imbalance less than 5°, the isolation of all ports is better than 38 dB and voltage standing wave ratio is less than 1.7.

Design a Multistub Array Antenna at 28 GHz with Beam Switching Ability

In this paper, a Millimeter Wave antenna is designed which has a compact, lightweight and planar configuration. The frequency band is 27–29.5 GHz as a candidate band for 5G/millimeter Wave (mmW) systems. The antenna structure is similar to Quasi Yagi antenna which has driver, director, feeding part, and reflector. Substrate Integrated Waveguide used for feeding part of single element antenna and Wilkinson power divider used for antenna array feeding network. The proposed antenna has been simulated, fabricated, and measured (S11, E, and H pattern). The simulation and measurement values showed good similarity. The switched line phase shifter used to consider the beam steering (rotation) ability of the designed antenna which is important in (mmW) systems such as RADARs and mobile handsets. To evaluate this ability, for 0 ° , 30 ° , 45 ° , and 90 ° phase differences, the beam steering angle ( θ ) simulated and also for − 90 ° and 90 ° implemented. The results showed that the efficiency, S11, and E patterns in the rotated beam is suitable and without degradation in antenna operation. To simulate and evaluate the designed antenna HFSS and CST Software are used.

A 5 × 8 Butler Matrix Based on Substrate Integrated Waveguide Technology for Millimeter-Wave Multibeam Application

A 5 × 8 Butler matrix (BM) operating in the millimeter-wave band is presented in this letter. The matrix is extended from two 3 × 4 Butler matrices by adding two couplers and one power divider, providing an equal amplitude signal distribution with five phase differences between the adjacent output port (0°, ±45°, ±135°). In order to reduce the number of crossover and complexity of the matrix structure, a dual-layer and symmetrical substrate integrated waveguide (SIW) structure is used to design the proposed BM. To verify the concept, an experimental BM is designed and fabricated as the feeding network of a slot antenna array, achieving five beams in the frequency range of 27.8-30.8 GHz.

Dual-Polarized Two-Dimensional Multibeam Antenna Array With Hybrid Beamforming and its Planarization

A feeding network crossing method is proposed to form an N $\times $ N dual-polarized two-dimensional multibeam antenna array (2D-MBAA) with analog-digital hybrid beamforming, which solves the problem of needing additional connection structure between the dual-polarized antenna array and analog feeding network for large-scale antenna arrays. The main design work is focused on the analog-beamformer (ABF) and two structures are proposed. One is vertical-crossed (VC) ABF and the other is parallel-crossed (PC) ABF, and the latter is a more complex design in exchange for a significantly reduced profile. As a verification, a $4\times 4$ dual-polarized 2D-MBAA with PC-ABF has been fabricated and tested. It is operated at 3.45GHz with a bandwidth of about 10%, and it can realize a scanning angle of ±45°.

Time-Modulated Arrays Controlled With Sinusoidal Pulsewidth Modulation

In this letter, sinusoidal pulsewidth modulation (PWM) is applied to the design of time-modulated arrays (TMAs). The array excitations are modulated using PWM-synthesized sine waveforms. This provides increased signal bandwidth, excellent rejection of the undesired harmonics, and modulation efficiencies aligned with the best ones in the literature. The simplicity of the technique allows for an easily implementable antenna array feeding network.

Design and Analysis of Antenna Feeding Networks Based on the Rotman Lens Using Interval Analysis (IA)

A new method for the design of antenna array feeding networks has been proposed in this work. In particular, the considered feeding networks are based on the Rotman lens. By knowing the maximum errors on the fabrication tolerances, the arithmetic of intervals and interval analysis (IA) are used for determining the lower and upper bounds of the antenna feeding network parameters of interest. Representative and preliminary numerical results are reported to show the potentialities of the proposed method. An experimental X-band Rotman lens prototype has been designed, fabricated, and assessed. The obtained results are quite good.

A Broadband $3\times4$ Butler Matrix and its Application in Multibeam Antenna Arrays

A novel broadband three-input four-output ( $3 \times 4$ ) Butler matrix is proposed in this communication. The proposed Butler matrix achieves equal power division and −90°, 0°, and +90° phase differences between output signals in the 2–4 GHz frequency range. By using the $3 \times 4$ Butler matrix as a four-element antenna array feed network, a broadside beam and two symmetrical beams are realized over a wideband frequency range. The proposed Butler matrix has been verified by measurements of S-parameters and radiation patterns using the broadband four-element antenna array. The measurement results are in good agreement with the simulation results. In addition, the proposed $3 \times 4$ Butler matrix can be extended for use with antenna arrays with a higher number of beams.

Analytical Evaluation of an Antenna Array System and Adaptive Cell Densification Technique for Energy Efficient LTE Network

This paper will propose a cost effective antenna array system and an adaptive cell densification technique for energy efficient Long Term Evolution mobile radio network. The antenna array system is designed to control the elevation half power beam width and elevation electrical beam down tilt angle by using a low loss novel antenna array feed network. The paper will also propose a novel sectorisation order control technique, which is the amalgamation of horizontal and modified vertical sectorisation with the improved and novel features. The proposed sectorisation order control technique can efficiently deal with uniform and non-uniform angular traffic loads in the dense urban region and therefore the proposed solution is more pragmatic. The results show that the capacity of the mobile radio network can be controlled with the highest possible flexibility by using the proposed cost effective antenna array system and adaptive sectorisation order control technique. The results also show that the 40 % energy can be saved when the traffic load of the base station is less than or equal to the minimum threshold value.

Design and Fabrication of Wideband Millimeter-Wave Directional Couplers With Different Coupling Factors Based on Gap Waveguide Technology

A class of wideband directional couplers suitable for achieving different coupling levels are proposed in this paper. The proposed couplers have been implemented using the double-layer groove gap waveguide at the millimeter-wave frequency range. They are composed of two parallel groove gap waveguide parts placed on top of each other in such a way that the coupling between the two waveguide sections can be achieved via the coupling structures placed in the common wall. Usually, the coupling layer consists of two rows of holes and depending on the number of holes the coupling levels can be controlled. The manifest and applicable property of the proposed directional coupler is that the coupling level can be simply changed using the different coupling layers without changing the top and bottom groove waveguides and transitions. As another significant advantage of the proposed coupler, there is no requirement of good electrical contact among different metallic parts of the structure, which considerably simplifies the manufacturing processes and mechanical assembly at millimeter-waves applications. For verification purpose, three sample couplers with coupling levels of 10, 20, and 30 dB have been designed, fabricated, and measured. To make the device accessible and measurable using the standard rectangular waveguides, two types of transitions from the groove gap waveguide to standard WR-15 are designed. The simulation and experimental results are in good agreement and show that the proposed couplers have large bandwidth for return loss level of 20 dB, coupling level of 10±1, 20±1, and 30±1 dB, and isolation level of 30, 35, and 40 dB over the desired frequency band of 50-70 GHz. The proposed directional couplers can be used as good candidates at millimeter-wave frequencies for probing and the design of compact integrated microwave circuits and systems, such as antenna array feeding networks.

A Novel Multifunctional EBG-Based Coupled-Line-Defect Directional Coupler Based on Layered Dielectric Substrates

In this paper, a novel multifunctional coupler based on line-defect layered electromagnetic bandgap (EBG) waveguides is proposed and studied. Extensive full-wave simulations are used to establish the critical nature of the coupling region for the realization of different functionalities of the coupler. Changing the separation between the rings or orientation of the rings in the coupling and/or channel regions leads to very interesting and unique coupling mechanisms, such as forward-wave, through-wave, and/or backward-wave quasi-0- and 3-dB couplers that distinguish the proposed topology from conventional proximity directional couplers. In the final analysis, one can switch between configurations by changing the orientation of the rings in the coupling region. These configurations with coplanar-slot-line feeding structures are fabricated and tested at X-band for demonstration purposes. Measurement results validated the design procedure and confirmed the general trends in simulations. The proposed EBG coupler is promising for beamforming matrix and antenna array feeding networks.

Line Defect-Layered EBG Waveguides in Dielectric Substrates

A dielectric-based multilayer structure composed of U-shaped rings (ML-UR) is used to develop a class of novel electromagnetic band gap (EBG) slab waveguide. The structure has two band gaps that narrow down as dielectric constant is increased. The EBG slab waveguide is created by embedding a single-layer line defect inside the 3D crystal of the EBG slab guide. Unlike our previously published foam-based EBG structure, the use of dielectric spacer in the EBG waveguides offers significant advantages in terms of overall size, structure reliability, and design flexibility. The waveguide structures reported in this paper are designed to operate at X-band (8–12 GHz) while being fed by coplanar-slotline transitions. Prototypes were fabricated and characterized experimentally. The insertion loss decreases by decreasing the number of full lattices of ML-UR surrounding the channels. The proposed waveguide has potential in microwave components such as directional couplers, phase shifters, and antenna array feeding networks.

Applications of Generalized Cascade Scattering Matrix on the Microwave Circuits and Antenna Arrays

The ideal lossless symmetrical reciprocal network (ILSRN) is constructed and introduced to resolve the complex interconnections of two arbitrary microwave networks. By inserting the ILSRNs, the complex interconnections can be converted into the standard one-by-one case without changing the characteristics of the previous microwave networks. Based on the algorithm of the generalized cascade scattering matrix, a useful derivation on the excitation coefficients of antenna arrays is firstly proposed with consideration of the coupling effects. And then, the proposed techniques are applied on the microwave circuits and antenna arrays. Firstly, an improved magic-T is optimized, fabricated, and measured. Compared with the existing results, the prototype has a wider bandwidth, lower insertion loss, better return loss, isolation, and imbalances. Secondly, two typical linear waveguide slotted arrays are designed. Both the radiation patterns and scattering parameters at the input ports agree well with the desired goals. Finally, the feeding network of a two-element microstrip antenna array is optimized to decrease the mismatch at the input port, and a good impedance matching is successfully achieved.

Substrate Integrated Waveguide Directional Couplers for Compact Three-Dimensional Integrated Circuits

A class of directional couplers based on the substrate integrated waveguide (SIW) technique for compact three-dimensional (3-D) integrated circuits is proposed and studied in this work. Backward and forward couplers as well as strong coupling-defined forward couplers are presented and developed. They are composed of two joined SIW sections such that the common wall between them is made of a portion of the broad side of the first SIW and the narrow side of the second SIW. This perpendicular topology is arranged and formed through the use of a LEGO-like interconnect between the two SIW structures. Different coupling geometries developed with a low-cost printed circuit board process are studied. Design considerations and measured results at $Ka$ -band are presented and discussed. To achieve respectively weak backward and forward directional couplings, Schwinger and multihole-type directional couplers are introduced first of all, which make use of coupling slots arranged around the center of the SIW broad wall. For each of those structures, a wideband 20-dB directional coupler is fabricated and measured for demonstration purposes. To achieve a strong coupling, a Riblet-type directional coupler is proposed and examined. Subsequently, a 3-dB coupler is demonstrated together with a 0-dB coupler, offering a wideband and very efficient transition between the perpendicularly arranged SIWs. The proposed directional couplers can be used at millimeter-wave frequencies for probing and the design of compact 3-D integrated circuits and systems such as polarimetric imaging radiometer or antenna array feeding networks.

Nonlinear analysis, design and radiation study of a single-beam CORPS-like active antenna array feed network integrated with single power amplifier, using a frequency-dependent behavioral model

A polynomial behavioral model of an appropriate single solid state power amplifier (SSPA) integrated with a coherently-radiating-periodic-structure-based antenna array feed network (C-AAFN) is prop...

Full-wave simulation, design and implementation of a new combination of antenna array feed network integrated in low profile microstrip technology

In this paper, a new modified combination of antenna and array feed network integrated in low thickness microstrip technology is presented. A concept similar to the concept of coherently radiating periodic structures is used to feed a 4-element antenna array. In the feed network, a new combination of Gysel-based 3 and 5 port components as power dividers/combiners is employed to propagate the power into the antenna array so that the desired Gaussian-like amplitudes and linear phase distributions can be obtained. These multi-port components are modified to design the feed network by single-layer microstrip technology without the matching and isolation circuits and through-substrate vias. Therefore, the manufacturing cost and difficulty and design complexity are reduced, considerably. Full-wave simulations of the feed network, unit cells and the final integrated antenna array are done, step by step and the results considering all possible losses are presented. To validate the designs, two prototypes, first the feed network and second the integrated module including both antenna array and feed network designed at 3.5 GHz were fabricated and measured and the S parameters (amplitude and phase) were compared with the full-wave simulations. A good agreement between the results including impedance and radiation characteristics is shown.

Microstrip Antenna Array With Series Feeding Network Designed With the Use of Slot-Coupled Three-Way Power Divider

A novel concept of a series feeding network of a microstrip antenna array has been shown. The proposed feeding network utilizes a four-port slot coupler as a three-way power divider, which is composed of two microstrip lines appropriately coupled through a slot within a common ground plane. The proposed power divider is used for simultaneous power distribution between two consecutive linear subarrays and between two 4 × 1 linear arrays constituting a single 8 × 1 linear subarray, where equal-amplitude and out-of-phase signals are required. Such a solution allows for realization of antenna arrays, in which all linear subarrays designed with the use of the “through-element” series feeding technique are fed at their centers from single transmission lines. The theoretical analysis as well as measurement results of the 8 × 8 antenna array operating within 10.5-GHz frequency range are shown.

Microstrip Antenna Arrays Fed by a Series-Parallel Slot-Coupled Feeding Network

A novel concept of a feeding network of a microstrip antenna array composed of series-fed linear subarrays has been shown. The proposed feeding network utilizes a concept of a slot coupler, in which two microstrip lines are coupled through a slot in a common ground plane. As it has been shown, such a slot coupler provides equal-amplitude and out-of-phase output signals and, therefore, can be used for appropriate feeding (at the center) of a single linear antenna subarray that utilizes “through-element” series-feeding technique. The proposed concept of a slot coupler has been used for the design of an 8 × 8 antenna array, in which all 8 × 1 linear subarrays are series-fed, whereas all 8 linear subarrays are fed by a parallel feeding network.

Novel circular in‐phase hybrid ring power divider

AbstractAn experimental investigation about the Circular In‐Phase Hybrid Ring power divider is presented. This device is a Five Ports Hybrid Ring that has potential applications in Antenna Array feeding Networks. Its principal behavior characteristics are analyzed and compared with a conventional device. A prototype, which includes the effects of SMA connectors, was designed and measured corroborating the behavior of this circuit as a conventional five ports microstrip hybrid. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2314–2317, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22714