A new triple band EBG unit cell with compact size has been designed, fabricated, and tested. The proposed EBG unit cell is based on a square mushroom-like EBG (M-EBG) structure with an interdigital coplanar waveguide (ICPW). With this technique, the size of the proposed ICPW-EBG structure has been reduced from λ/2 to λ/4 compared with the conventional M-EBG unit cell dimension, which is 18 × 18 mm². The proposed unit cell was designed in order to respond for three frequency bands at 1.8 GHz, 2.45 GHz, and 3.7 GHz. An array of 10 × 10 unit cell was also designed as a reflector with an overall dimension of 181.8 × 181.8 mm². The dipole antennas were implemented over the designed reflector with a short distance of λ/8 to radiate electromagnetic wave. The simulation results showed that the ICPW-EBG reflector can improve directivity of the dipole antenna to be 9.12 dB at 1.8 GHz, 9.02 dB at 2.45 GHz, and 8.40 dB at 3.7 GHz. The measurement directivities agreed well with simulation results including 8.72 dB at 1.8 GHz, 8.56 dB at 2.4 GHz, and 8.1 dB at 3.7 GHz. This is the first design of triple band EBG unit cell with 50% size reduction compared with the conventional structure at the same frequency. The designed ICPW-EBG reflector with dipole antenna results in the triple band operation, low-profile and high gain suitable for modern wireless communication systems.

中文翻译：

---

使用叉指共面波导结构的紧凑三频EBG，用于增强天线增益

已经设计，制造和测试了一种新型的紧凑型三频EBG晶胞。提出的EBG晶胞是基于带有叉指共面波导（ICPW）的方形蘑菇状EBG（M-EBG）结构。与传统的M-EBG晶胞尺寸（18×18 mm ^2）相比，采用该技术所提出的ICPW-EBG结构的尺寸已从λ / 2减小至λ / 4 。设计提出的单位单元是为了响应1.8 GHz，2.45 GHz和3.7 GHz的三个频段。还设计了一个10×10晶胞阵列作为反射镜，其总尺寸为181.8×181.8 mm ²。偶极天线经设计的反射器中实现具有短距离λ/ 8辐射电磁波。仿真结果表明，ICPW-EBG反射器可以将偶极天线的指向性提高到1.8 GHz时为9.12 dB，2.45 GHz时为9.02 dB，3.7 GHz时为8.40 dB。测量方向性与仿真结果非常吻合，包括1.8 GHz时的8.72 dB，2.4 GHz时的8.56 dB和3.7 GHz时的8.1 ​​dB。这是三频EBG晶胞的首个设计，与相同频率下的常规结构相比，其尺寸减小了50％。设计的带有偶极天线的ICPW-EBG反射器可实现三频运行，低剖面和高增益，适用于现代无线通信系统。