Equal Power Division Research Articles

Design of millimeter wave dual‐polarized multibeam antenna array with a boresight beam

A design of millimeter wave (mm-wave) dual-polarized multibeam antenna array (MAA) with a boresight beam is presented. In order to generate a boresight beam, a 5 × 6 Butler matrix based on three-way directional couplers is designed as the beamforming network, which achieves equal power division and −60°, +120°, 0°, −120°, +60° progressive phase differences among the output ports when the five input ports are excited, respectively. By four-layer design, the two 5 × 6 BMs for horizontal polarization (HP) and vertical polarization (VP) are constructed. The patch is used as radiator element, and the HP and VP wave are excited by aperture coupling and microstrip feed, respectively. A prototype is fabricated and measured to verify the design. The measured results show that the designed mm-wave dual-polarized MAA can generate five radiation beams including a boresight beam and the five beams with HP and VP cover the range of ±50° at 28 GHz. In addition, the designed mm-wave dual-polarized MAA can be a potential option for mm-wave multibeam application.

Compact Ultra-Wideband Wilkinson Power Dividers Using Linearly Tapered Transmission Lines

In this work, compact extended ultra-wideband (UWB) Wilkinson power dividers (WPDs) using tapered transmission lines are analyzed, designed, and measured. Utilizing carefully designed tapered transmission sections results in widening the operational bandwidth and reducing the element dimensions. Analytical models and design procedures of simple and compact and equal and unequal UWB WPDs based on linearly tapered transmission lines are developed and outlined in this paper. Four different configurations of equal and unequal power dividers are designed and presented. The number and locations of the isolation resistors have a noticeable effect on extending the operational bandwidth of the dividers. The presented designs of the WPDs have superior performance over extended bandwidths. The simulation and experimental results are in very good agreement with good insertion and return loss, good matching, and isolation, over the extended UWB operational bandwidth from 3 GHz to 27 GHz.

A novel single layer SIW 6 × 6 beamforming network for 5G applications

A novel single layer 6 × 6 beamforming network (BFN) based on substrate integrated waveguide (SIW) is proposed for 5G applications. The proposed BFN is realized by 3 × 3 multi-aperture couplers (MACs), hybrid couplers, phase shifters, and crossovers. The BFN is designed for equal power division and ± 30°, ± 90°, ± 150° phase difference between output signals in the 28–32 GHz frequency band. By feeding a 6 × 2 SIW slot antenna array with proposed BFN, a six-beam antenna is implemented that generates six symmetrical beams in the ± 11°, ± 31°, and ± 52° directions. To confirm the simulation results, the proposed six-beam antenna is fabricated and measured. The simulation and measurement results show that the six-beam antenna has good radiation patterns, −10 dB impedance bandwidth from 28 GHz to 32 GHz, and a 3-dB wide-angle coverage of about 150°. The size of the antenna is 106 × 31.8 × 0.787 mm3, which is suitable for 5G applications.

N-Way Reconfigurable Power Divider With Parallel Reconfigurable-Characteristic-Impedance Transformation Lines

An <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> -way reconfigurable Power Divider (PD) based on parallel reconfigurable-characteristic-impedance transformation lines is proposed in this article. The characteristic impedance of the transmission lines in the power division network is constant, making it suitable for realizing a multiway reconfigurable PD. The reconfigurable parallel characteristic impedance transformation lines are composed of coplanar waveguides and the p-i-n diodes. Reconfigurable star isolation networks with zero-phase transmission lines are used to improve isolation. By making the p-i-n diodes under different bias conditions, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{N} - 1$ </tex-math></inline-formula> states of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> transmission modes can be realized. For verification, a six-way simplified reconfigurable PD is designed and fabricated; 21 states of 6 transmission modes of the PD are realized. The measured insertion losses of the six-way reconfigurable PD in six transmission modes are less than 1.89 dB. The measured isolations between transmission ports and isolation ports are greater than 30.3, 32.8, 33.3, and 35 dB, while in those modes, the isolations between the input port and isolation ports are greater than 27.1, 29.1, 29.8, and 32.4 dB. The current study is restricted to the case of PDs with equal power-division action to be more specific.

Design of Wilkinson power divider at 28 GHz for 5G applications

A power divider &lt;span&gt;plays a significant function in antenna’s feeding network. Many types of power divider exist yet there are only a few existing studies of Wilkinson power dividers at high frequencies (28 GHz) for 5G communications systems. This paper presents a tapered 2-way Wilkinson power divider that operates in Malaysia's 5G wireless communication band (28 GHz). CST microwave studio is used to design, simulate, and optimize the tapered 2-way Wilkinson divider. The simulation results show resonance around 23.5-37.9 GHz. The operating frequency of 28 GHz resulted in power division with a 3.2 dB insertion loss and has an isolation of 19.21 dB. The design can be made wideband with equal power division at each output port by adding an extra resistor along the tapered line to reduce output return loss and isolation, as demonstrated in this paper.&lt;/span&gt;

Wideband Hybrid Couplers With Unequal Power Division/Arbitrary Output Phases and Applications to Miniaturized Nolen Matrices

In this article, a new design approach for developing hybrid couplers with arbitrary power division and the phase difference is presented. The design is based on a transformer-based coupler with high isolation between sum and difference ports. Based on this model, a modified coupler is developed by including two L-shaped networks to produce constant phase differences at two output ports. Slotlines and microstrip-to-slotline transitions are used for expanding the bandwidth and introducing a 180° phase difference at the difference port. Two prototypes with equal and unequal power division are designed and verified. Experimental results reveal that the proposed designs can achieve constant phase difference, low insertion loss, and satisfactory matching across a broad bandwidth of more than 40%. Based on the proposed designs, a simplified multibeam Nolen matrix is also designed utilizing only three hybrid couplers and no phase shifters. The compact beamforming network demonstrates that the proposed component is very useful for size reduction in wireless communication systems.

Design and implementation of compact tri- and quad-band SIW power divider using modified circular complementary split-ring resonators

AbstractThis paper presents a miniaturized tri- and quad-band power divider (PD)based on substrate integrated waveguide (SIW). By adopting different types of modified circular complementary split-ring resonators on the top surface of SIW, multiple passbands are generated propagating below the SIW cut-off frequency. The working principle is based on evanescent mode propagation that decreases the operating frequency of the PD and helps in the miniaturization of the proposed structure. The operating frequency of the proposed PD can be individually controlled by changing the dimensions of the resonator. To verify the proposed concept, a tri-band and a quad-band PD exhibiting 3 dB equal power division at 2.41/3.46/4.65 GHz and 2.42/3.78/4.74/5.8 GHz are designed using the full-wave simulator, validated through circuit model, fabricated and experimentally verified. The measured results agree well with the simulations. The proposed PDs have good performance in terms of reasonable insertion loss, isolation, minimum amplitude and phase imbalance, smaller footprint, easy fabrication and integration. The size of the fabricated prototype is 18.3 mm × 8.4 mm, which corresponds to 0.205λg × 0.094λg, λg being the guided wavelength at the first operating frequency.

Highly Miniaturized Dual-band Power Divider based on HMSIW for 5G/ WLAN Applications

A highly compact dual-band power divider (PD) based on the HMSIW structure is investigated in this paper. The dual-band operation is achieved by incorporating an inner modified circular complementary split-ring resonator (MC-CSRR) and outer circular CSRR on the top metal layer of HMSIW. The operating frequency of the PD decreases due to evanescent mode propagation. This assists in miniaturizing the structure apart from the 50% size reduction offered by the HMSIW. By asymmetric placement of two output ports of a PD, it is possible to achieve an unequal PD with an arbitrary power division ratio. To exhibit the proposed idea, two dual-band PD prototypes, one with equal power division and the other with unequal power division are designed, fabricated and experimentally verified. The PD occupies a compact size of 0.128 λg× 0.122 λg, where λg being the guided wavelength at the first operating frequency. The proposed PD with advantages of lower insertion loss, better return loss, minimum amplitude and phase imbalance between the output ports is beneficial for 5G FR1 n78 (3.3- 3.8 GHz) and WLAN (5.17 GHz) communications.

Wideband aperture coupled substrate integrated waveguide power divider based on half mode analysis

A wideband substrate integrated waveguide (SIW) power divider based on half mode analysis is presented in this article. The structure is constructed by two substrate layers and three metal layers. Two symmetrical longitudinal apertures etched on the middle ground are introduced to realize the equal power division, and couple the signal from the SIW to the upper layer output ports simultaneously. Two fork-type microstrip lines on the top metal layer are used to improve the bandwidth of the power divider. The equivalent circuit based on the half mode analysis method is presented for theoretical analysis and further design of the power divider, and good impedance matching can be obtained accordingly. For demonstration, a power divider prototype with the dimension of 48 × 73 × 1.38 mm3 is designed, fabricated, and measured. Good agreement is observed between the simulated and measured results. The measured return loss of the SIW power divider is better than 12 dB in the frequency range of 6.2 ~ 10.3 GHz, and the insertion loss is around 1.6 dB over the entire frequencies of interest.

Design and simulation of low side lobe micro-strip array antenna at multiple frequencies

In this paper, we present a simple design of a feed network for the antenna to achieve a lower side lobe level. Side Lobe Levels (SLL) are critical issues in the detection of an object. Higher side lobe levels can increase the false detection of objects in an autonomous vehicle system. The array is designed and simulated for four different frequencies, one at a time to make it a scalable design. The chosen frequencies are 10 GHz, 15 GHz, 20 GHz, and 24 GHz. The feed network design consists of eight patch elements with an equal power divider and CST studio software is used for simulations. From simulation results, it can be observed that VSWR is equal to 1.26, 1.16, 1.62, and 1.05 at respective frequencies. So, the radiation efficiency can be achieved as -1.14 dB, -0.92 dB, -0.46 dB, -0.41 dB. The results substantiate that proposed design can reduce the SLL more than -24.5 dB in the elevation plane and also it is greater than 14.4 dB at all the aforementioned frequencies.

Design of wideband multi-layer quadrature hybrid couplers with butterfly shaped resonators

AbstractIn this paper, a wideband quadrature hybrid coupler is presented. The proposed structure has a multi-layer microstrip topology. In this topology, there are three substrate layers including prepreg material and four conductive layers. In order to achieve equal power division between through and coupled arms of the directional coupler while maintaining a 90° phase shift, aperture coupling between the resonators located at both top and bottom layers is utilized. So as to avoid any unwanted effects of prepreg material in such multilayer topology, via shielding around resonators are inserted. In this study, coupling from input ports to output ports is accomplished by the shielded butterfly shaped slot etched to the ground layer of top and bottom layers. The proposed design operates within 3–12 GHz. The acquired phase imbalance between the coupled ports is &lt;±2.5°. The results of the manufactured quadrature hybrid coupler agree well with the simulated results.

Single-Ended-to-Balanced Broadband/Filtering Planar Magic-Ts With High Common-Mode Suppression

In this article, a single-ended-to-balanced (SETB) broadband magic-T based on microstrip/slotline transitions and microstrip/slotline T-junctions is proposed. For the purpose of miniaturization and low interconnection loss, an SETB filtering magic-T with a sharp selectivity is also achieved by introducing a pair of microstrip stub-loaded resonators (SLRs) at the two output ports. For the first design, a U-type microstrip feed line integrated with a circular slot stub is adopted at each output port, which makes the differential-mode (DM) response independent of the common-mode (CM) one. Therefore, the design procedure is simplified significantly. Meanwhile, based on the microstrip/slotline T-junctions, in-phase and out-of-phase two-way equal power division networks can be realized, respectively. For the second design, a DM passband with two transmission zeros (TZs) is generated by introducing SLRs based on the first design. By employing the characteristic mode analysis method, it is easy to find that the center frequency and fractional bandwidth (FBW) can be controlled by changing the dimensions of SLR. To the best of the authors' knowledge, the SETB magic-T with broadband or filtering performances may be the first ever reported. To verify the feasibility of the designs, two prototype circuits of the proposed magic-Ts are fabricated and measured. The simulation results are in good agreement with the measured ones. In these two designs, the functions of in-phase and out-of-phase power dividing, broadband or frequency selectivity, isolation between output ports, and CM suppression can be realized at the same time.

A Compact Quadruplexer-Integrated Filtering Power Divider

A compact quadruplexer with the functions of frequency division, frequency selection, and power splitting/combining is presented in this article. Four tri-mode stub-loaded resonators were adopted to construct the compact multifunctional quadruplexer with a third-order filtering response. The four-channel passbands of the quadruplexer were controlled and realized independently by using the distribution coupling configuration. The output coupling structure was designed to be symmetrical with equal power division for each channel. To achieve a satisfactory isolation performance, a resistor was loaded between the open ends of the output coupled lines for each channel. A microstrip multifunctional quadruplexer operating at 1.1, 1.44, 1.73, and 2.06 GHz was fabricated. The prototype circuit size of the multifunctional quadruplexer was only approximately 0.4 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> × 0.59 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> . Moreover, the output isolations were >27 dB within the entire frequency bands.

Ku-band 8-way Wilkinson power divider based on ridge gap waveguide technology

The novel ridge-gap waveguide (RGW) technology which has recently been introduced has many advantages in micro/mm-wave frequencies such as low loss, broad bandwidth, low sensitivity to manufacturing errors and easy integration with active components, etc. In this paper, a Ku-band 8-way Wilkinson power divider (WPD) is proposed and simulated based on the RGW technology for the first time, to the best of our knowledge. An RGW-toWR62 transition is also designed and simulated. The proposed 8-way RGW-based WPD with WR62 transitions shows low-loss equal-power division in phase with good matching at all ports and isolation between output ports in the Ku band. The proposed RGW-based WPD can be extended to an arbitrary -way corporate power divider/combiner which can find many applications such as in array antenna feed networks, solid-state power amplifiers (SSPAs), etc.

A Method for Designing Unequal Power Divider for Implementing Antenna Array Excitations

In this paper, a method for designing a feeding network to obtain a low peak sidelobe pattern of an 8*1 linear antenna array is proposed. The optimized element weights were first obtained using genetic algorithm. Then two different networks based on equal and unequal power dividers are designed for the linear antenna arrays. In an equal power divider structure, the power is divided equally into all branches of the network to reach the final ports, while in the unequal structure; the division is only made equal in some branches and unequal in other branches to build an unequal power divider. In the two methods, the design process is based on two stages, the first stage uses a T-junction power divider, and the second stage a Wilkinson power divider is used. In an equal power divider, T-junction and Wilkinson divide the power equally, while in the case of an unequal power divider the T-junction divider is only unequal. In the two designs, the feeding network is designed according to the following specifications: the substrate (FR-4 with ϵr =4.3) and ground dimensions are 440.4mm × 103.8mm ×1.6 mm and 440.4mm × 103.8mm × 0.035mm respectively, and at a resonant frequency of 2.36 GHz. The simulation results showed the effectiveness of the designed power dividers that to be used as a feeding network in the linear antenna arrays.

Development and Thorough Investigation of Dual-Band Wilkinson Power Divider for Arbitrary Impedance Environment

In the design and development of front-end communication systems, the arbitrary impedance environments are encountered frequently. In this article, a three-port dual-band equal power divider is proposed which also transforms all types of impedance environments at its ports inherently. The power divider is suitable for a wide range of arbitrary frequency ratios and impedance terminations at each of the input and output ports. A systematic design procedure with a design flow graph is provided. The closed-form design equations make the design process simple and quick for prototyping purposes. The proposed design approach enhances the design flexibility significantly with the presence of multiple independent variables. Design examples with distinct design specifications are provided to demonstrate the effectiveness and flexibility of the architecture. A prototype working at 1/2.6 GHz and with frequency-dependent complex load (FDCL) terminations at the input and output ports is fabricated and measured to validate the proposed architecture and design methodology. The proposed dual-band impedance transforming power divider exhibits controllable bandwidths, planar structure without any reactive element, compact size, and the ability to provide port matching for any real, complex, and frequency-dependent complex impedance terminations.

Implementation of inkjet‐printed 3 dB coupler with equal power division and 45° output phase difference

AbstractImplementation of a 3 dB coupler with flexible phase difference was presented in this paper. The coupler has equal power division and output phase difference of 45° as against the conventional coupler. It has advantage in many applications that require phase delay like phased antenna array, and beamforming network without necessarily requiring additional phase shifters. It was designed and implemented using the instant inkjet printing technique on a transparent Polyethylene terephthalate (PET) substrate specially coated with resin. The coupler's response shows very good return loss and isolation of −28 and −48 dB, respectively. A bandwidth of 31.33% was achieved around the center frequency. However, an output phase difference of 45° was recorded with a slight phase variation of about ±1° within the specified bandwidth.

A high-efficiency near-field focused transmitting antenna based on the equal power divisions

For microwave power transmission (MPT), the transmitting (Tx) array with a tapered amplitude distribution can achieve a maximum beam collection efficiency, but it needs a feeding network with an arbitrary power division ratio; thus, it is complicated and costly in practical applications. This work explores realizing high transmission efficiency by a Tx array with the equal-ratio steps amplitude distribution (ERSAD). By using the ERSAD, the amplitude value of the central units of the Tx array is uniform, and the amplitude feeding of the edge units only needs equal power divisions. Thus, the amplitude feeding is greatly simplified. Besides, a compensated phase distribution is used to focus the radiating beam on the receiving aperture. To validate the proposed design, a Tx antenna consisting of 8 × 8 units with a total aperture size of 1 × 1 m2 is designed. The operating frequency and the focused distance are 5.8 GHz and 10 m, respectively. A 64-way microwave power source is used to adjust the amplitude and the phase of the Tx array, and an MPT experiment is conducted. The measurement shows that, compared with the 10 dB Gaussian amplitude array, the proposed array nearly has the same transmission efficiency against different receiving apertures.

A Low-Profile Beamforming Patch Array With a Cosecant Fourth Power Pattern for Millimeter-Wave Synthetic Aperture Radar Applications

In this article, a novel beamforming patch array with a cosecant fourth power pattern is proposed for millimeter-wave synthetic aperture radar (SAR) applications. It enables radar receiving identical power in the field of view, provided that the radar cross section levels of targets within the illuminated area are similar. Different from “one-way” communication application, the SAR is a “two-way” system such that the received power is inversely proportional to $R^{4}$ , not $R^{2}$ , where $R$ is the distance between target and radar. Thus, conventional cosecant squared patterns are not suitable for SAR. Here, the concept and link properties of the proposed cosecant fourth power pattern are introduced, while its synthesis process is facilitated by a mixed optimization method, including nonlinear fitting and active pattern methods. As demonstrated, an array prototype, which consists of 12 series-fed patch subarrays and a substrate integrated waveguide network for power distributing and phase shifting, is designed and fabricated. Particularly, the power-distributing section only consists of symmetrical T-junctions with equal power division, thus making the antenna more tolerant to fabrication error. Good cosecant fourth pattern performance is achieved from 23.8 to 25.0 GHz. The presented array also owns the advantage of low profile ( $\sim 0.09\lambda _{0}$ ), compact, reliable, and low cost.

Compact wideband differential filtering power divider based on three‐line coupled structure with lumped elements

A wideband differential filtering power divider using three-line coupled structure with multiple lumped elements is proposed. The equal power division ratio, filtering response, isolation and common-mode suppression are mainly derived from the symmetrical structure, three-line coupled lines with capacitors, resistors and the short lines along the vertical symmetrical line, respectively. Compared to the reported differential filtering power dividers, the proposed design shows advantages of wide bandwidth, compact size and low insertion loss (IL). A prototype with the small size of 0.5λ g × 0.08λ g (λ g is the guided wavelength at the centre frequency) was designed for demonstration, which exhibits the 3 dB fractional bandwidth of 79.2% and the minimum IL of 0.48 dB.