A Novel Ultra Compact Four-way Power Divider with Integrated Filtering Function for WLAN Applications Ahmed M. Hussien, 2Yasser S. Farag, and 3 Ahmed F. Daw 1 4 Mahmoud A. Abdalla Electronic Engineering Department MTC College Cairo, Egypt 4 email@example.com Electronics and Communications Department MSA University, Cairo, Egypt 1 firstname.lastname@example.org, 2 email@example.com, firstname.lastname@example.org of LR and CL then shunt combination of LL and CR connected to the ground with via. This circuit is claim with the single band filtering response characteristics that are required for this proposed divider. Abstract?A four-way ultra-compact power divider is proposed in this paper for antenna array applications. The power divider is constructed based on composite right/left handed microstrip structure. The analytical analysis are presented. The divider operates at 5.2 GHz for WLAN services. This paper introduces equivalent circuit, 3D full wave simulation, and in addition to that, this design realizes compactness size 20�mm2, (0.62�186) ?2g. Keywords?Ultra Compact divider, CRLH four way-power divider, WLAN applications, filtering divider. I. INTRODUCTION Nowadays, expanding requests in the modern wireless and mobile communication frameworks lead to the fast enhancement for presenting RF components with single filtering characteristic, having more compact size .The composite right left handed transmission line (CRLH-TL) has been applied in many microwave components design. Power dividers are the key segments to acknowledge numerous important RF applications like RF power amplifier, quadrature adjusted RF mixer, resonators. A few past reviews have been executed many sorts of power dividers -. As the minimization of size of power dividers is our interest. This paper presents a compact four way power divider with filtering responses for suitable for array antenna. A high selectivity is required to suppress unwanted signals, single filtering function particulars appropriate for WLAN applications. The whole four-way power divider is minimum with size of 20.4�mm2. II. Fig. 1. Block diagram for integrated phase array antennas with power divider and phase shifters. DESIGN OF FOUR WAY NOVEL POWER DIVIDER One of the hot topic for WLAN applications is the integrated subsystem for serving this band. The block diagram is shown in Fig.1 it shows that, the subsystem of WLAN band urgent need mainly three components; compact power divider, phase shifters, and array antennas. The main goal for this paper is to present new configuration of very compact four way power divider that is suitable for WLAN system. The main concept to design a compact power divider is to implement matching unit cell of CRLH transformer to match between the inputs and outputs terminals. The equivalent circuit for CRLH unit cell is presented in Fig.2 (a). It is constructed with- series combination 978-1-5386-3284-0/17/$31.00 �17 IEEE Fig. 2. (a): Equavelent circuit for CRLH unit cell, (b); Layout for single CRLH unit cell. 465 AP-S 2017 The analysis of this circuit based on microwave periodic analysis is clam that CRLH TL has left and right handed passbands at lower and higher frequencies, respectively. The basic important step for designing the CRLH transformer it is the cut-off frequencies for pass band. These values could be calculated based on ?d to be either zero or ?, where: cos ?d ? 1 ? ZY 2 functions. The simulated 3D model scattering parameter phase for the designed CRLH cell of the four way power divider is shown in Fig.4. As appeared in the figure, the transmission coefficients has 90 degrees was accure two times during the pass band at 4.8 GHz, and 5.6 GHz. The compassion between the proposed ultra-compact power divider with the recent power dividers are presented in table (I). As tabulated, the comparison introduces that the effective circuit size of proposed power divider is very compact compared with the recent introduced dividers. (1) cos ?d ? 1 ? ?d 2 2 ?C L ? C L ? 1 ? ?? R ? R ?? ? R R ? ? [? LR C R ? 2 ? LL C R ? C L LL ? 4C L LL ? ?2 (2) Finally, the cuttoff frequencies will be resented as: ? 1 f c1 ? min ? ? 2? ? ? 1 f c 2 ? max ? ? 2? ? 1 1 , 2 LL C R ? 1 LL C R , 1 2? ? ? ? ? (3) ? ? LR C L ?? (4) 1 LR C L 1 Based on the above equations (3), and (4) the cuttoff frequencies are selected to be 5 GHz for lower cut off and 6.5 GHz at the higher cut-off. The layout of the CRLH unit cell is presented in Fig.2 (b). Fig. 4. Magnitude and phase responses for purposed integrated filtered CRLH power divider. The proposed layout of the CRLH filtered power divider are illustrated in Fig. 3 with the total all compact size equals 20�mm2 (0.62�186) ?2g. The design of this proposed power divider has been designed on Rogers substrate with a thickness of 1.52 mm, a dielectric constant of 3.55. TABLE I. COMPARISON WITH EXISTING POWER DIVIDERS Proposed Effective circuit size (?2g) 0.62�186  0.54�45 17 15  0.62�186 13 6.42  0.92�4 20 6.18  0.87�35 15 6.44 Ref Return loss (dB)(center) Insertion loss (dB) 6.4 6.19 IV. CONCLUSION This paper has presented ultra-compact four way power divider integrated with filtering for WLAN applications, compatible with phase array antennas subsystems. The created results outcomes represent transmission coefficients equals ? 6.4 dB, and the return loss equals 17 dB at 5.2 GHz. Additionally, the proposed size is equal 20�mm2 (0.62�186) ?2g. Fig. 3. Four-way ultra-compact power divider layout for WLAN applications. III. RESULTS OF PROPOSED POWER DIVIDER REFERENCES The designed lumped element CRLH structure has been realized using distributed elements in asymmetric loading configuration to minimize the power divider size. The dimensions are designed based on the equivalent circuit model lumped components values. An extra tuning has been carried out using 3D electromagnetic full wave simulation.    The four way power divider presents return loss 10 dB extended from 5 GHz till 6.5 GHz, and reach to 22.5 dB at 5.2 GHz as shown in Fig.4. The insertion loses is 6.4 dB from 5 GHz to 6 GHz. Moreover, the passband filter support WLAN applications based on the introduced design with bandwidth equal 1.3 GHz. The utilized CRLH TLs are intended to have a function impedance transformer, in order, to achieve a matching   466 Ahmed F. Daw, Mahmoud A. Abdalla, and Hadia M. Elhennawy "DualBand Divider Has Rejection Band at 5 GHz", Microwaves and RF Magazine, Vol. 11, no.1, Nov. 2016. T. Zhang, W. Che, H. Chen and W. Feng, "A Compact Four-way Dualband Power Divider Using Lumped Elements," in IEEE Microwave and Wireless Components Letters, vol. 25, no. 2, pp. 94-96, Feb. 2015. N. Gao, G. Wu and Q. Tang, "Design of a Novel Compact Dual-Band Wilkinson Power Divider With Wide Frequency Ratio," in IEEE Microwave and Wireless Components Letters, vol. 24, no. 2, pp. 81-83, Feb. 2014. M. J. Park, "Two-Section Cascaded Coupled Line Wilkinson Power Divider for Dual-Band Applications," in IEEE Microwave and Wireless Components Letters, vol. 19, no. 4, pp. 188-190, April 2009. M.-J. Park and B. Lee, ?A dual-band Wilkinson power divider,? IEEE Microw. Wireless Compon. Lett., vol. 18, no. 2, pp. 85?87, Feb. 2008.