Four‐way waveguide power divider design for W‐band applications

In this article, a four‐way waveguide power divider is proposed for W‐band applications. The waveguide power divider employs an improved H‐plane T‐junction configuration. With the introduction of a metallic tetrahedral protrusion into the waveguide junction, good impedance matching can be achieved within a wide frequency range. First, a two‐way power divider is designed and analyzed, achieving almost identical amplitude and phase response at its two output ports. Then, other two same T‐junctions are cascaded, respectively, at the two output ports of the two‐way power divider to realize the proposed four‐way power divider. The four‐way power divider has been optimized, fabricated, and measured. The measurement results agree with the simulation ones reasonably, which demonstrates that the input return loss of the proposed four‐way power divider maintains above 14 dB across the entire W‐band with an insertion loss of less than 1.3 dB. Therefore, it could find wide applications in W‐band power splitting and combining modules.     

Equal and unequal quad‐band Gysel power dividers

This article presents for the first time a quad‐band Gysel power divider capable of achieving equal and unequal power division at four arbitrary frequencies. The structure of the proposed divider is similar to its single‐band counterpart but loaded with quad‐band reactive networks. The design procedure and theoretical analysis of the proposed divider are presented. A quad‐band Gysel power divider with equal division and another with 2:1 unequal division are designed at the operational frequencies of 0.85, 1.6, 2.4, and 3 GHz. Simulation and measurement results of the two dividers are presented, and good performance is observed at each band. For both designs, the realized power division ratios are within 1 dB from their ideal values, whereas the matching and isolation levels are below ?10 dB at the four bands.     

A broadband coplanar waveguide to rectangular waveguide power divider using a slot

In this article, a broadband coplanar waveguide (CPW) to rectangular waveguide power divider using the dipole slot is proposed. The power divider consists of an input CPW port and two output rectangular waveguide ports. The CPW to rectangular waveguide power divider using the dipole slot has a return loss larger than 15 dB and an insertion loss equal to 3.08–3.27 dB in the whole X‐band (8.2–12.4 GHz). Furthermore, to broaden the bandwidth, the dipole slot is replaced by the bow‐tie slot. The CPW to rectangular waveguide power divider using the bow‐tie slot yields a return loss larger than 16 dB and an insertion loss equal to 3.05–3.29 dB from 8 to 13 GHz, which exceeds the X‐band. To verify our design, power dividers that use the dipole slot or the bow‐tie slot are fabricated and measured. The measurement results of both power dividers are in good agreement with the simulation results. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Dual‐passband bandpass‐filtering power divider using half‐mode substrate integrated waveguide resonator with high frequency selectivity

In this paper, a half‐mode substrate integrated waveguide (HMSIW) power divider with bandpass response and good frequency selectivity is proposed. The proposed power divider includes input/output microstrip lines, four HMSIW resonators, cross‐coupling circuits, and an isolation resistor. The dual‐band bandpass‐filtering response is obtained by using the dual‐mode slotted HMSIW. To get good frequency selectivity, the input/output cross‐coupling circuits have been used, and several transmission zeros can be observed. A dual‐band filtering‐response HMSIW power divider is designed, fabricated and measured. The total size of the fabricated power divider is 0.58λg × 0.45λg. The measured results show a reasonable agreement with the simulated ones. The measured central operating frequencies of the dual‐band HMSIW power divider are at 2.43 and 3.50 GHz, respectively. The measured 3‐dB fractional bandwidth is about 13.3% and 6.3% in the two passbands, and the measured output isolation is about 20 dB.     

A novel power divider with ultra‐wideband harmonics suppression based on double‐sided parallel spoof surface plasmon polaritons transmission line

A novel wideband power divider with ultra‐wideband suppression of harmonics is proposed in this paper. The power divider is composed of double‐sided parallel spoof surface plasmon polaritons transmission line (DSP‐SSPP‐TL) with periodical grooved bow‐tie cells. The cut‐off frequency of DSP‐SSPP‐TL can be flexibly adjusted by changing the parameters of bow‐tie cells. To demonstrate that, dispersion relations of the bow‐tie cells with different parameters are simulated, and three DSP‐SSPP‐TL counterparts are experimented. Then, a power divider centered at 3.31 GHz (f₀) is designed, fabricated, and measured. Experimental results indicate that the 10‐dB return loss bandwidth of the proposed power divider is about 146% from 0.9 to 5.73 GHz, and the upper stopband is extended up to 40 GHz (12.1 f₀) with the suppression level above 32 dB. Moreover, ultra‐wideband isolation between two output ports of the proposed power divider could be achieved by employing two lumped resistors between two DSP‐SSPP‐TLs.     

Generalized high‐isolation n‐way Gysel power divider with arbitrary power ratio and different real terminated impedances

An exact closed‐form design approach for a generalized high‐power n‐way Gysel power divider is proposed. The power divider could be designed to achieve an arbitrary power ratio with the flexible multiway application, arbitrary real terminated impedance, excellent isolation, and easy fabrication through both planar and three‐dimensional structures. Moreover, this improved power divider could maintain high power processing capacity through the coaxial cavity transmission line and grounding resistances. The exact analytical solutions related to ideal port matching and high isolation are obtained based on the circuit and transmission‐line theory. To verify the proposed approach, a compact 3‐way coaxial power divider with a pre‐designed power ratio of 1:1.5:2 and four different real terminated impedances of 50, 55, 60, and 65 Ω is designed and fabricated. Excellent agreement is achieved between the simulated and measured results. Measurements from 4.7 to 5.7 GHz show that the return losses of all input and output ports are better than 15 dB. The maximum insertion loss is 0.5 dB, and the phase imbalance is approximately less than 6.1°. In addition, the isolation between any two output ports is better than 23 dB from 4.5 to 6 GHz. Meanwhile, the power handling capability can reach the maximum power of the commercial 50 Ω SMA connectors (2.098 kW).     

Dual‐band filtering power divider with unequal power division ratio and low‐loss characteristic

In this article, a dual‐band filtering power divider with unequal power‐division ability is proposed. Different from conventional equal power dividers constructed by filters or coupled resonators, noncoupled structures are employed in this design. As a result, low‐loss characteristic is realized for the proposed power divider. In this proposed structure, the dual‐band unequal power allocation is realized by replacing conventional single‐band λ/4 transformers with dual‐band ones (T‐junction structures). Three identical λ/4 stepped impedance resonators are properly attached to all the three ports of the proposed power divider to generate an extra transmission zero between two operational bands. Therefore, a filter‐like shaping in its S‐parameter results is obtained. A resistor is located between two outputs for output isolation. Mathematical derivations of the overall design procedure are also provided based on the circuit models and transmission line theory. Meanwhile, a resistor for output isolation is also included between two outputs, whose value can be calculated using given equations. For validation, a prototype operating at 0.9 and 2.1 GHz are designed, fabricated, and measured. The isolations between two outputs are 30 and 26 dB while the phase differences are only 2.5°and 4.9° at 0.9 and 2.1 GHz in the measurement, indicating good consistence of outputs. Measured |S21| and |S31| are ?(1.76 + 0.3) dB, ?(4.77 + 0.2) dB at 0.9 GHz and ?(1.76 + 0.6) dB, ?(4.77 + 0.5) dB at 2.1 GHz.     

A Ka‐band power divider/combiner using two side‐inserted magnetic coupling semicircular ring probes

A Ka‐band power divider/combiner with dual magnetic coupling semicircular ring probes is proposed in this paper. Firstly, a broadband microstrip‐to‐waveguide transition with semicircular ring probe is designed based on the side‐inserted structure of magnetic field excitation in a rectangular waveguide. The insertion loss of the proposed transition is less than 0.7 dB in Ka‐band assisted by the dual symmetrical broadband probes and rectangular waveguide. Then, the divider/combiner is proposed using the new transition with magnetic coupling from narrow wall into the rectangular waveguide. The bandwidth of the divider/combiner is more than 9 GHz (from 27 to 36.7 GHz), and the insertion loss of the single divider/combiner is less than 3.3 dB. Finally, the performance of the proposed divider/combiner is validated through simulations and measurements. The proposed design has potential applications in microstrip circuits.     

An efficient method of designing dual‐ and wide‐band power dividers with arbitrary power division

Capability of microstrip nonuniform transmission lines (MNTLs) for construction of dual‐band and broadband unequal Wilkinson power dividers with arbitrary‐way, arbitrary frequency band operations, and arbitrary power divisions is evaluated. Also, the MNTL transformers are introduced for dual‐band/broadband matching of the unequal output impedances of the MNTL power divider with arbitrary output terminal impedances. The strip width of MNTLs is considered variable and is written as a truncated Fourier series expansion. To show the validity of the design procedure, three experimental MNTL Wilkinson power dividers, which are dual‐band two‐ and three‐way power dividers with different power divisions working at 1 and 3.4 GHz and one broadband equal power divider working from 0.4 to 1.8 GHz, have been designed and fabricated. In the first ones with power division of 1.5, outputs isolation and ports matching of less than ?30 dB are achieved. Next, an extended recombinant structure is presented for achieving three‐way MNTL power dividers with dual‐band operation. The measured isolation between outputs and ports matching are better than 30 dB and measured forward transmissions are between ?4.87 and ?5.45 in two passbands of the divider. Also, for the proposed broadband divider, the measured isolation between the outputs is better than 13 dB in 127% desired bandwidth. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Double‐layer microstrip ultra‐wideband filtering power divider with high selectivity and large isolation

In this article, a compact double‐layer microstrip ultra‐wideband (UWB) filtering power divider with high selectivity and isolation is proposed. The filtering power divider consists of a multimode resonator at the top layer coupled with a pair of branch lines at the bottom through a slotline in the middle ground. The slotline provides strong coupling between the two layers and equally distributes the power to two branch lines. The resistor loaded about a quarter‐wavelength away from the slotline achieves high isolation within UWB range. The UWB filtering properties with controllable transmission poles and zeros as well as power splitting with enhanced isolation have been analyzed. The adjustable transmission zeros of the filter unit enables the bandwidth control of the filtering power divider. Finally, a UWB filtering power divider operating at 3.1 to 10.6 GHz has been designed, fabricated, and measured. It achieves a compact size of only 26 × 28 mm², high isolation about 20 dB, and good out‐of‐band suppression of 40 dB.     

A W‐band broadband power divider/combiner using two parallel antisymmetric tapered probes

In this article, a broadband microstrip‐to‐waveguide transition with antisymmetric tapered probe as well as a W‐band power divider/combiner using dual proposed antisymmetric tapered probes is presented. Because of tapered microstrip shapes and metallic steps, the proposed transition is proved to be broadband, efficient, and compact. The insertion loss of the transition sample is less than 0.56 dB between 75 GHz and 100 GHz. Under the assistance of the gradually changed waveguide and dual parallel tapered probes, the operating band of the power divider/combiner has been significantly improved, which is adequate to work in the whole W‐band. A back‐to‐back prototype of the divider/combiner is fabricated and measured. The measured insertion loss of the single divider/combiner is less than 0.29 dB between 90 GHz and 100 GHz, and agrees well with the simulations. Because the circuit size is smaller than 8.0 mm × 2.2 mm (Thanks to the excellent performance and compact size), the proposed design can find wide applications in miniaturized MCM/MMIC systems.     

A novel symmetrical Wilkinson power divider for dual‐band application

A symmetrical two‐way Wilkinson power divider with shifted output ports, much wide bandwidth and large frequency‐ratio is proposed for dual‐band application. The corresponding transcendental design equations are derived by using the even‐ and odd‐mode analysis. Moreover, the closed‐form scattering parameter expressions are derived. Transcendental design equations are solved and accurate numerical design parameters along with different frequency ratios are obtained. Finally, the proposed structure and design method are validated by simulated and experimental results of typical microstrip planar power dividers, the performance is clearly observed for the input and output matching, isolation and transmission characteristic very well at the two band frequencies. More specifically, the measured transmission characteristics of the divider are 3.11 dB/3.58 dB at the 1.0 GHz/3.5 GHz, respectively. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:102–108, 2014.     

Design of an ultra‐wideband power divider with harmonics suppression

The design of an ultrawideband (UWB) power divider with harmonics suppression is presented. With the proposed approach, the size of the quarter‐wavelength transmission line can be reduced and the high order harmonics can be suppressed. The design equations are deduced by transmission line theory. A prototype power divider operated at UWB band is designed and fabricated. Experimental results show good performance of the proposed design. In addition, a stop‐band with rejection level more than 20 dB is from 17.3 to 24.5 GHz. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:299–304, 2015.     

Modified Wilkinson power divider with harmonics suppression and compact size for GSM applications

In this article, a modified microstrip Wilkinson power divider with harmonics suppression for GSM communications applications is presented. For low‐pass filter designing, one open stub, one radial resonator, and two rectangular resonators are used. According to results related to insertion losses (|S₂₁| and |S₃₁|), stopband is wide and equal to 7.5 GHz (3.4‐10.9 GHz), under the condition of 20 dB harmonic suppression level. The results show that at the designed frequency of 1.8 GHz, the input return loss (|S₁₁|) and output return losses (|S₂₂| and |S₃₃|) are better than 22 dB, and the isolation between of output ports (|S₃₂|) is better than 30 dB. The size of the proposed power divider is compact and equal to 10.6 × 14.6 mm². Finally, the proposed power divider was fabricated and the measurement results illustrate a good agreement with simulation results.     

A micro compact coplanar power divider at X-band with finite-width ground plane based on GaAs MMIC technology

A micro coplanar Wilkinson power divider at X-band on GaAs substrate is presented in this paper. The proposed power divider introduces a size reduction method, and the length of the transmission line is reduced to λ/8 (at 10 GHz). Since the two segments of the two edge coupled quarter-wave asymmetric coplanar striplines (ACPSs) with finite-width ground plane are closed to each other, their characteristic parameters, such as characteristic impedance and attenuation coefficient, are obtained using the quasi-static conformal mapping technique (CMT) of coupled coplanar waveguide (CCPW) with finite-width ground plane. S-parameters for the power divider are deduced in the case of quasi-static TEM even–odd mode. The fabrication process is compatible with the GaAs MMIC process. The measured S-parameters are compared with the simulated results of HFSS v.11 and the calculated results of TEM even–odd analysis. Simulated results show that it has reflection loss less of 16.5 dB and insertion loss less of 3.6 dB. Measured results show that the divider has reflection loss less of 15.0 dB and insertion loss less of 3.5 dB. Compared with conventional Wilkinson power divider, the length of the power divider is shortened from 2,620 to 1,570 μm.     

A novel differential filtering SIW power divider with high selectivity

A novel differential power divider with bandpass filtering response using the substrate integrated waveguide (SIW) technology is presented. An SIW resonant cavity operated in a balanced resonant mode with odd symmetric electric field distribution is utilized to provide both balanced inputs/outputs and expected common‐mode (CM) suppression in a certain band. Meanwhile, by properly constructing the cross‐coupled topology of SIW resonant cavities, the proposed differential power divider achieves a high‐selectivity bandpass filtering response with two transmission zeros on both sides of the passband. The differential power divider is designed and prototyped on a single‐layer printed circuit board (PCB). The measured center frequency is at 10.6 GHz with 490 MHz 3‐dB bandwidth. A good CM suppression can also be achieved within the operating band. The measured in‐band differential‐mode imbalance for magnitude is ±0.3 dB, while for phase is 0°–4°. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:182–188, 2016.     

Composite corporate traveling‐wave power dividers for slot array waveguide antennas

A composite corporate traveling‐wave power divider is presented. The single‐layer structure is composed of three parts: two interdigital traveling‐wave subsections combined with a power splitter. An iterative design technique is described in which the divider is split into a number of basic blocks. Large‐scaled networks are then easily designed because the whole structure does not need to be simulated. A method to take into account the insertion losses is also proposed and bandwidth enhancement is discussed, which is done by increasing the number of corporate layers. Experimental results are also shown for a 1:4 subsection. It provides equal output power with 0.5 dB of insertion loss. The phase‐shift between output ports is close to the specifications of ?150° at 30 GHz, with an error of less than 2°. It is also shown that this topology is well suited for frequency scanning antenna. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

General design of impedance‐varying multi‐way Wilkinson power divider with bandwidth redefinition characteristics

In this article, a general design methodology of a multi‐way compact equal split Wilkinson power divider (WPD) with bandwidth redefinition characteristics and planar structure is proposed. Quarter‐wave matching uniform transmission lines in the conventional design are replaced with non‐uniform transmission lines (NTLs) governed by a truncated Fourier series. Even mode analysis is adopted to obtain NTLs with predefined bandwidth functionalities; whereas several isolation resistors are optimized in the odd mode analysis to achieve proper isolation and output ports matching over the frequency range of interest. Compactness is achieved by incorporating only one quarter‐wave wideband NTL transformer, with a length computed at the center frequency, in each arm. Two 3‐way WPDs with different frequency bands (i. e., 5‐9 GHz and 4‐10 GHz) and one 5‐9 GHz 4‐way divider examples are designed and simulated. Furthermore, a wideband 3‐way WPD operating over 4‐10 GHz band is fabricated and measured. Results show input and output ports matching and isolation below ?15 dB, and transmission parameters in the range of [–4.9,–6.2] dB and [–6,–7.5] dB across the operating band of the 3‐way and 4‐way WPDs, respectively.     

A novel balanced wideband power divider based on microstrip‐slot transitions

A novel design of a balanced wideband power divider (PD) with enhanced common‐mode (CM) suppression is proposed. The top and bottom layers of the structure contain tapered microstrip line. Those microstrip lines are coupled via slotline in the ground plane, which is located at the middle layer. With appropriate placement of the slotline, the coupling between the slotline mode and the differential‐mode (DM) signals can be maximized, while that between the slotline mode and the CM signals can be minimized. Simulated and measured results show that the proposed PD has equal power division, low insertion loss, and good return loss. In the measurement, the fractional bandwidth of the measured ?10 dB (DM) return loss is about 101% (1.82–5.35 GHz), the insertion loss for the DM signals is less than 5 dB, the suppression of the CM signals is higher than 45 dB, and the DM isolation is better than 10 dB over the fractional bandwidth. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:437–442, 2014.     

Multiway wideband power dividers

In this article, we propose a new design methodology to broaden the bandwidth of a multiway Bagley power divider (BPD). Single‐frequency matching uniform quarter‐wave‐length microstrip lines in the conventional design are replaced with impedance‐varying transmission lines of broadband matching characteristics. The equivalent transmission line model is used for profiling impedance variations, which are governed by a truncated Fourier series. Such variations are determined by finding the optimum series coefficients that result in a wideband matching nature. The proposed technique leads to flexible spectrum allocation and matching level. Furthermore, the resulting structures are compact and planar. First, analytical results of three 3‐way BPDs of different fractional bandwidths are presented and discussed to validate the proposed approach. Then, two examples of 3‐ and 5‐way BPDs with bandwidths of 4–10 GHz and 5–9 GHz, respectively, are simulated, fabricated, and measured. Simulated and measured results are in a good agreement, with input port matching of below ?15 dB and ?12.5 dB for the 3‐ and 5‐way dividers, respectively, over the bands of interest. The obtained transmission parameters of the 3‐ and 5‐way dividers are ?4.77 ± 1 dB and ?7 ± 1 dB, respectively, over the design bands. The proposed wideband dividers find many applications in microwave front‐end circuitry, especially in only‐transmitting antenna subsystems, such as broad‐ and multicast communication links. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:730–738, 2015.