{"id":233602,"date":"2022-08-23T17:18:10","date_gmt":"2022-08-23T17:18:10","guid":{"rendered":"\/forum\/forums\/topic\/pml-boundaries-on-mode-eme-not-giving-proper-s-parameters\/"},"modified":"2022-08-23T17:18:10","modified_gmt":"2022-08-23T17:18:10","slug":"pml-boundaries-on-mode-eme-not-giving-proper-s-parameters","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/pml-boundaries-on-mode-eme-not-giving-proper-s-parameters\/","title":{"rendered":"PML boundaries on MODE EME not giving proper S Parameters"},"content":{"rendered":"<p>I am running Lumerical 2021 R1.4.&nbsp;<\/p>\n<p>A confusing problem happened: when using EME to design a taper, I get pretty normal results when I use Y symmetric or antisymmetric boundary conditions, but when I run the same simulation with PML boundary conditions, the S parameters go to very small values (&lt;1e-15). This is a large disparity dispite the nearly identical field profiles.<\/p>\n<p>When the EME taper examples are run with the three boundary conditions mentioned here, we get the following (graphs are for S21 vs group span during span sweep):<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2022\/08\/23-08-2022-1661274739-image.png\" alt=\"\"><\/p>\n<p>This problem is present in our custom taper designs as well, and it makes us doubt our simulation fidelity. To my knowledge, all-PML should match at either anti symmetric or symmetric in a geometriy that is symmetric about that axis.<\/p>\n<p>Changing energy conservation from passive to conserve energy did not help when I tried that.<\/p>\n","protected":false},"template":"","class_list":["post-233602","topic","type-topic","status-closed","hentry","topic-tag-MODE-1","topic-tag-modeexpansion-1","topic-tag-photonics"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["261942","2592"],"_bbp_author_ip":["23.218.93.53"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["752"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["233602"],"_bbp_forum_id":["27833"],"_bbp_engagement":["2592","261942"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["233623"],"_bbp_last_active_id":["233623"],"_bbp_last_active_time":["2022-08-23 20:15:22"]},"test":"jacob-campbellgtri-gatech-edu"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/233602","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/233602\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=233602"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}