# A 3.7 GHz CPW Filtering Antenna with a Pair of Gain Zeros

^{1}

^{2}

^{3}

^{4}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. CPW Filtering Antenna Design

#### 2.1. Structural Construction

#### 2.2. Transmission Line Analysis

_{1}is the impedance of the CPW uniform impedance resonator with a width of wu1. The corresponding electric length is shown in Figure 2. The equivalent circuit of the odd mode is provided in Figure 3b, and that of the even mode is provided in Figure 3c, where Z

_{2}= Z

_{3}= Z

_{4}= Z

_{1}.

_{m}, is equivalent to a short-circuited CPW line, and the electric length of the transmission line can be derived as ${\theta}_{m}=arvtan\left(2{Z}_{1}{W}_{od}{L}_{m}\right)$, where ${W}_{od}$ and ${W}_{ev}$ represent the resonant angular frequency of the odd mode and the even mode, respectively.

## 3. Design Analysis and Results of the CPW Filtering Antenna

#### 3.1. S-Parameter and Gain of the CPW Filtering Antenna

#### 3.2. Patterns and Current Profile of the CPW Filtering Antenna

#### 3.3. Fabrication and Experimental Results

#### 3.4. Performance Comparisons

## 4. Conclusions

## Author Contributions

## Funding

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 2.**Bandpass filter section. (

**a**) Bandpass filter topology. (

**b**) CPW and the filter coupling structure.

**Figure 3.**Equivalent TL model of the 2-order split ring CPW resonator with SEMC. (

**a**) Total equivalent TL circuit. (

**b**) Circuit of the odd mode. (

**c**) Circuit of the even mode.

**Figure 5.**S11 and gain of the filtering antenna versus parameter s3. (

**a**) S11 versus s3. (

**b**) Filtering antenna gain versus parameter s3.

**Figure 6.**S11 and gain of the filtering antenna versus parameter wu2. (

**a**) S11 versus wu2. (

**b**) Gain versus wu2.

**Figure 13.**Measured filtering antenna patterns. (

**a**) E-plane (xoz) pattern. (

**b**) H-plane (yoz) pattern.

W | L | w1 | g1 | wu1 | wu2 | lu1 |
---|---|---|---|---|---|---|

70 | 70 | 1.5 | 0.5 | 1.2 | 1.5 | 12.2 |

lu2 | s1 | s2 | s3 | r1 | r2 | w2 |

12.2 | 0.2 | 0.1 | 0.2 | 16 | 19 | 29 |

References | Center Frequency (GHz) | Gain Zeros | Spurious Responses | Bandwidth Controllable | Max. Gain (dBi) | Circuit Type | Size (mm ^{2}) |
---|---|---|---|---|---|---|---|

[4] | 2.45 | no | no | na | 2.41 | microstrip | 43 × 30 |

[5] | 3.95 | no | yes | na | 4.3 | microstrip | 30 × 20 |

[8] | 2.45 | no | no | na | −1.3 | microstrip | 60 × 70 |

[11] | 0.67 | 2 | yes | na | 4.2 | microstrip | 80 × 80 |

[19] double stub | 3.6 | no | yes | - | 3.13 | microstrip | 35 × 44 |

[20] | 3.6 | no | yes | - | 2.57 | microstrip | 35 × 44 |

[21] | 3.68 | no | no | - | 2.2 | microstrip | 24.2 × 27 |

This work | 3.7 | 2 | no | yes | 2.98 | CPW | 70 × 70 |

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**MDPI and ACS Style**

Xue, Y.; Dong, Y.; Huang, W.; Yan, R.; Xiang, J.; Wang, P.
A 3.7 GHz CPW Filtering Antenna with a Pair of Gain Zeros. *Electronics* **2023**, *12*, 2145.
https://doi.org/10.3390/electronics12092145

**AMA Style**

Xue Y, Dong Y, Huang W, Yan R, Xiang J, Wang P.
A 3.7 GHz CPW Filtering Antenna with a Pair of Gain Zeros. *Electronics*. 2023; 12(9):2145.
https://doi.org/10.3390/electronics12092145

**Chicago/Turabian Style**

Xue, Yulei, Yanchen Dong, Weiping Huang, Ruiqiang Yan, Jiaqiang Xiang, and Peng Wang.
2023. "A 3.7 GHz CPW Filtering Antenna with a Pair of Gain Zeros" *Electronics* 12, no. 9: 2145.
https://doi.org/10.3390/electronics12092145