**5. Conclusions**

In this paper, a new dual-band balanced bandpass filter (DB-B-BPF) with inherent common-mode rejection is presented. The proposed structure is based on the use of two pairs of magnetically coupled open-loop resonators implemented in multilayer technology. The lower differential-mode (DM) passband is created by the middle layer resonators, while the upper DM passband is associated with the top layer resonators. By using this configuration, it is possible to design the two DM passbands with independent control of bandwidth and matching level. At the same time, very good band-to-band isolation and common-mode rejection is achieved. To demonstrate the usefulness of this proposal, an example of a filter operating for GPS and Wi-Fi applications (1.58 GHz and 2.4 GHz) was designed, fabricated and measured. Experiments show a Common-Mode Rejection Ratio (CMRR) better than 38 dB and 31.1 dB for the lower and upper DM passbands, respectively. Measured DM insertion loss for both passbands is 0.92/1.94 dB and the obtained 3-dB bandwidth is 8.86/5.69 %.

**Author Contributions:** J.L.M.d.R., A.L. and A.F.-P. designed, simulated, manufactured and measured the filter prototype. F.M., J.M. and A.J.M.-R. supervised the whole study. All the authors participated in writing the paper and in revising the article. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work has been funded by the Spanish AEI Ministry of Science, Innovation and Universities and EU Feder Funds (project TEC2017-84724-P). J.M.R. acknowledges financial support of a research scholarship of the Spanish Ministry of Education (reference PRE2018-085677).

**Conflicts of Interest:** The authors declare no conflict of interest
