摘要

本論文目的是建立一套標準的4G頻帶夾心帶線型環行器設計流程，
中心頻鎖定為4G頻帶中的0.9GHz。本文先探討電磁波在鐵氧體
中的非互異性質以及損耗特性幫助我們選擇適合的設計磁場。再來進
行雙Ｙ結理論的運算來決定帶線的形狀和鐵氧體的尺寸，最後再利用
HFSS（High Frequency Structure Simulator）進行結構優化。
設計好的環行器經過加工後，使用PNA向量網路來測量它的傳輸特性
。我們使用電磁鐵和永久磁鐵作為外加磁場。環行器的操作頻
帶為 872 MHz 至 928 MHz (6.22%) Insertion loss 大於-0.3 dB Reflection和Isolation小於-20 dB。

Abstrcat

This paper establishes a standard process to design stripline circulator operating at 0.9 GHz for 4G communication. First, the non-reciprocal properties
and underlying loss mechanism of EM waves in ferrites
was analyzed that helps us to select the proper
operating magnetic field. Based on the aforementioned knowledge, we further employed the double-Y-junction
theory for designing the shape of stripline as well the dimension of ferrite. Finally, the fine structure of circulator was optimized by using HFSS (High Frequency Structure Simulator).
The designed circulator was fabricated and its transmission characteristic was experimentally measured by PNA (performance network analyzer, ) under the magnetic field applied by permanent magnet and electromagnet.
The operating band (insertion loss > -0.3 dB) ranging
from 872 MHz to 928 MHz (6.22%) was observed, in which
the reflection and the isolation are less than -20 dB.

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